soon getting a 425, and I want to know what the quarter mine, 0-60, maximum speed ect. are. Its one of the 4bbl carb ones. can anyone help me out?

1/4 mile.... my '79 Sedan DeVille d'Elegance ran the 1/4 in 17.5s @78mph, all stock... she was a bit faster when I was done with her.

0-60....10 seconds? Dunno, I have a handful of movies you could time it tho...

top speed.... actually reached in 2nd gear, and thats around 115mph.

180hp, 320ft-lbs torque.... never goes above 2,000RPM unless the secondaries are open. Nail it from 30 and the fun begins, she'll go sideways from a stop too.... atleast mine did...

awesome cars.... I miss my 425 and my '79...

Thanks Rick :)

17.5 seems a little odd to me, I mean the HT4100 does 17.7 @75 or something like that, and people always say it SO slow... but this is hardly any faster? WTF?

God that's depressing. 425 cubic inches and 180 horsepower.

Thanks Rick :)

17.5 seems a little odd to me, I mean the HT4100 does 17.7 @75 or something like that, and people always say it SO slow... but this is hardly any faster? WTF?

I doubt it's anywhere near 17.7, maybe like 18.7 and that's on a good day.

Actually, they say that the 425 makes up in torque what it lacks in hp.

17.7 is just what I was told, I thought it seemed a little quick too, but hey, if thats true, its ok with me :D

Its not the size of the engine... well, actually it is...

Hey thats right, you have a '79, what do you think of engine?

I remember reading in a road test from '81 that an '81 Sedan deVille is good for a 18.6 in the 1/4 mile and I think it's 0-60 was like 10.8 or so I think. I'm probably a bit off though.

I can see that, the V8-6-4 is like an iron HT4100 as far as power goes. yet I really wish I could drive a 368, just to see what it feels like, I've driven almost everything else that came in this bodystyle

425 ('79) well, soon...
HT4100 ('83)
350 ('90)
305 ('91)

now all I need is 307 and 368 with and w/ out V8-6-4

The 368 was a lot like the 425, it pulled real well, from a dead stop, and was pretty quiet in my Eldo, I always wished that car had a 4 speed trans with OD it would have been so much better

I drove a '81 Brougham Coupe once, it reminded me of that '90 Brougham D'Elegance 307 I drove....slow.

Thanks Rick :)

17.5 seems a little odd to me, I mean the HT4100 does 17.7 @75 or something like that, and people always say it SO slow... but this is hardly any faster? WTF?

I don't think the RWD HT4100 was that fast....

Wasn't a race car, but it held its own... by the time I was done with it, I am sure I had her in the 16's..... and that was all just minor stuff.

Out of the '77-'92 generation, the 425 is the most powerful, and almost the fastest... the 350 in the '90-'92 has the edge, but its also using another gear and a much lower final drive.... thats a Chevy for ya! ;).... Still tho, Cadillac 425 > Chevy 350.

Actually, they say that the 425 makes up in torque what it lacks in hp.

17.7 is just what I was told, I thought it seemed a little quick too, but hey, if thats true, its ok with me :D

Until you throw a tach on the 425 and watch it while driving, you'll never understand the amount of torque shes got.

Unless you open the secondaires, she'll never go above 2,000RPM..... it'll rise 300RPM in between gears, then shift and drop 300RPM, then rise again... all that while accelerating from 35-60 without any issue.

Put all the weight you want in it, she may ride a little low, but you'll never feel it in the throttle..... it was a beast.

I can see that, the V8-6-4 is like an iron HT4100 as far as power goes. yet I really wish I could drive a 368, just to see what it feels like, I've driven almost everything else that came in this bodystyle

425 ('79) well, soon...
HT4100 ('83)
350 ('90)
305 ('91)

now all I need is 307 and 368 with and w/ out V8-6-4

368 (V8-6-4) wasn't too bad of an engine..... and the V8-6-4 operating in V8 mode was the same as the regular 368.

You also forgot to mention the 4.1 Buick V6 and the Olds 350 diesel :).

Of all the engines throught the years of this generation, my personal list is:

425 (always a spot in my heart for it)
368/V8-6-4 (just cause its a BB Cad... and the V8-6-4 is a really cool system)
Olds 350 diesel (Honda-like MPG from a big body Caddy)
Olds 307 (will never, ever die) <--- those last 3 are held very close together

Then the HT4100, I have no desire for, nor the Buick V6..... the 305 I woudln't even look at... and the Chevy 350... only if I wanted performance out of the box... I don't care for Chevy engines tho.... nor do I think a small block should be in these cars.... if I am gonna make one fast, its getting a big block Olds or a big block Caddy....somewhat easy enough. If i wanted mileage (awesome highway cruiser) then it'd be the Olds 350 diesel... then the V8-6-4, tho they were about even with the 307/200R4

I like my 425 a lot. It's not the fastest thing I've driven by far, but it feels very strong.

Out of the '77-'92 generation, the 425 is the most powerful, and almost the fastest... the 350 in the '90-'92 has the edge, but its also using another gear and a much lower final drive.... thats a Chevy for ya! ;).... Still tho, Cadillac 425 > Chevy 350.

Just think if the 425 had a 4 speed with a 3.08:1 rear end!!

Just think if the 425 had a 4 speed with a 3.08:1 rear end!!

No good.

BB Cads like to tug, then sit at a low RPM....

different mindset then building a Chevy... Chevys lack the low end torque of the Cad, they need low gears to get them off the line, and then overdrive to keep the RPM down on the highway so it wont burn itself up.

BB Cads like high gears, they like to tug, engine accelerates slowly while car accelerates fast.... then for the highway, it dosn't need overdrive because it would just end up bringing the RPM too low.... BB Cads perform best (most highway MPG and engine is most "happy" ) when the cruise RPM is at peak torque (as with most cars) With my 2.28 gears that would be 2,000RPM right around 73 or so..... at that speed mileage was starting to go down due to aerodynamics of the body.... but right around 70 she would get around 18mpg... not too bad IMO.

The best trans for a BB Cad is the Turbo400, bar none. People that have built Chevies their whole life, then attempt a BB Cad end up runing it... they will throw in some insane gear like a 3.73, then have overdrive.... that'd be like putting the 2.28's and 3spd on a 350... it'll work, but it wont be happy at all.

Although the 3.08 you mentioned would be almost ideal, actually thats pretty much as low as I'd go with a BB Cad, but the overdrive isn't needed... it dosn't like to race thru the gears... it'll run better, and actually accelerate the car faster by tugging.

You can really hop up the performance on a 425 car with basic work... dumping the 2.28's for something like a 2.56-3.11 would help alot... but even then, I kept the 2.28's and got her going pretty fast... off the line, despite all the torque, she would bog, just because trying to get 5,000lbs moving with 2.28 gears would be like trying to push a football player with your pointer finger.... but 25mph+ and it was quick... floor it from 30 and it would downshift into first, actually push you in the seat and youd see the front end lift.... I miss that car.

The downshift at 30, does that feel the same as in our deVilles?



Now I know this is kind of a hard comparison, but does the low end power of the 425 compare to the low end power of the 4.9, or is it a totally different ballpark?

Oh, also, what grade of gas should I use? the guy I bought it from said it will run good on 87, but it runs better with 89.

I use the mid grade (89) if I use 87 she gets unhappy, runs but unhappy. Last week I spent $71 to fill her up!:alchi:

I used to run premium (93) in mine, then I just started running regular (87) in it... no difference in performance or mileage... with 8.2:1 compression, it will run on regular just fine.

the 30mph run.... the 4.9 is quicker, lighter, better gearing etc... it was alot different with the 425, there is alot more mass its moving aorund, so it felt alot different... its a shame I can no longer compare the two.

I drove a '81 Brougham Coupe once, it reminded me of that '90 Brougham D'Elegance 307 I drove....slow.

Chadillac,

You're talking about my poor old '81 Coupe that you drove last fall when it was sick. FYI, just got the V8-6-4 running properly, somehow, and the performance is greatly improved. Comparing the '81 with 368 FI to the '79 with 425 carb, I have to say I really like the fuel injection for the velvet smoothness but I love the brute feel of the 425. I wish my 425 had FI!

I love reading about Rick's performance testing on the '79 he had (sorry you lost it). I'm pretty much a chicken to pound my cars since they are old and I'm afraid I'll break them. That's probably bad thinking since they are over built Cads from the good old days! :)

Dave

I had lots of fun with that car... it never once gave me any problems.

I see it as, if its going to break, its going to break. But with a big block Cad, a Turbo400 and a GM 10-bolt 8.5" rear end, all in a passenger car... the driveline is so solid, that breaking anything is really out of the question.

Plus, if it breaks, I would fix it... it was easy. For a 27 year old car with 93k miles, I still used it as a daily driver, and besides its thirst for gasoline, it never once even blinked.

No good.

BB Cads like to tug, then sit at a low RPM....

different mindset then building a Chevy... Chevys lack the low end torque of the Cad, they need low gears to get them off the line, and then overdrive to keep the RPM down on the highway so it wont burn itself up.

I guess the 300 ft. lbs. I have at 2000 RPM in my '90 is lacking then.......

Chadillac,

You're talking about my poor old '81 Coupe that you drove last fall when it was sick. FYI, just got the V8-6-4 running properly, somehow, and the performance is greatly improved. Comparing the '81 with 368 FI to the '79 with 425 carb, I have to say I really like the fuel injection for the velvet smoothness but I love the brute feel of the 425. I wish my 425 had FI!

I love reading about Rick's performance testing on the '79 he had (sorry you lost it). I'm pretty much a chicken to pound my cars since they are old and I'm afraid I'll break them. That's probably bad thinking since they are over built Cads from the good old days! :)

Dave


Oh I didn't mean any offence of any sort Dave. Just coming from a more modern, lighter car with a more powerful engine to your big and awesome '81 is like stepping into a totally different ballpark. But you car has a lot more presence and charisma than mine, and isn't that what a Cadillac is supposed to be? If I was to drive it again, I'm sure the performance would be much improved! I drove a '84 Sedan deVille last month with the HT4100 and I was actually kinda impressed all things considered with the around town power and that car has 5 less hp and 65 less lb/ft of torque!

I guess the 300 ft. lbs. I have at 2000 RPM in my '90 is lacking then.......


No no, that was plenty of low end power! Almost like driving that LT1 I had! Too bad I couldn't find any new pavement to drive on ;)

Ha, you wouldn't need it now buddy! I put the initial timing up to 12* now, and it woke her up even more!

I know for a fact that a 5.7 Brougham (like yours Brian) will beat a 425 Brougham in the 1/4 mile. It's about a .4 second difference.

Yes, but would it beat a coupe Deville? being that the coupe is lighter. If so thats just sad, a small block out running a 425.

Not bad at all. I just don't get the comparison between SBC and BBC. Whether it's an Olds, a Buick, a Chevy, Pontiac, or Cadillac, the differences between a SB and a BB just make comparing the two apples to oranges. Like Rick said, the SBC and SBO D-bodies have deeper rear-ends and another gear to grab with, because they need them. That's fine, but you can't simply say one is better than the other, because they are vastly different.

Wow, hit a rough spot?

I just don't care much for small blocks... everyone has got them, to me, there is nothing special about a Chevy 350. I also don't like the idea of a Chevy engine being in a Caddy.

a 350 will beat a 425? Gosh, I'd hope so... but only by .4 seconds? Come on guys, with atleast 11 years advancement in car and engine deisgn, a whole extra gear and 3.08 gears vs. 2.28, I would sure hope it'd be faster. Put the 350 behing a Turbo400 and 2.28 gears and you'll bog it down, not only will it not be happy at all around town, but it would be stressed on the highway because of the lack of overdrive. On the same note, put 3.08 gears behind even a stock 425, and we'll see which is faster now.

Sorry, there is no replacement for displacement, thats why guys stroke their 350 to 383.

Seems like this turned into a SBC vs. BB Cad war here..... plenty of people like their Chevys... I am just not one of them... for me, its all about Cadillac and Oldsmobile engines.

well, the 350 in my '90 is sort of slow from like 35 on. it gets off the line good, but zero highway power IMO. is the 425 the same way?

the 425 never felt "slow"... even at 75 on the highway, put it to the floor, the secondaires open and it downshifts to 2nd, and it would actually pull hard until its top speed aorund 115.

If anything, the 425 is slowest form 0-30, despite all the torque, trying to get 5,000lbs moving with 2.28 gears can be quite the task... so nail it from a stop it would chrip the tires, but kinda bog... once it hit 25-30 it would pick up really nice.

Yes, but would it beat a coupe Deville? being that the coupe is lighter. If so thats just sad, a small block out running a 425.

No, it's not sad, it's a fuel-injected small-block with 9.3:1 compression (9.8 in '91 and '92) versus a total smogger tiny big block with low compression. Can't really compare the two, but other factors, as has been mentioned many times play a big part.

a 350 will beat a 425? Gosh, I'd hope so... but only by .4 seconds? Come on guys, with atleast 11 years advancement in car and engine deisgn, a whole extra gear and 3.08 gears vs. 2.28, I would sure hope it'd be faster.

I don't want this to turn into a Cad vs. Chev war, but I see the argument from the other side. An engine with as large a stroke as a 425 only has 320 ft. lbs? Really, a 425 is like an overbored 350 with a 4.06" stroke. Shouldn't the 425 be walking all over the 350, even with 2.28 gears?

I don't want this to turn into a Cad vs. Chev war, but I see the argument from the other side. An engine with as large a stroke as a 425 only has 320 ft. lbs? Really, a 425 is like an overbored 350 with a 4.06" stroke. Shouldn't the 425 be walking all over the 350, even with 2.28 gears?

Lets keep in mind shes got 8.2:1 compression, is almost the smallest, least powerful big block Cad.... in a time when the industry was moving from gas guzzling beasts to smaller more fuel efficent engines.... meaning, the enigne had alot of smog control devices, all very early systems so it wasn't really made to work with it well...

The 425 isn't some magical engine in itself... but it holds its own, and its got lots and lots of potential as well. Personally, IMO, the big block Cads are the best gasoline V8's made.... thats just how I feel, I personally never gave much thought into the Chevy enignes.... you just see them all over... how many 350's can you look at, at a car show before one becomes like the last? For that reason I am always looking at the oddbals... Caddy V8's if there are any... Olds etc... even the stright 6's, slant 6's etc.... I get tired of seeing the same thing. I also don't think a SBC should be in a fullsize Cad... the only exception being the '93-'96 Fleet, with the LT1... and even then, it was the only engine at the time worty of being used in that configuration...

Gotta realize that the 425 and the 350 were serving 2 different purposes... the 425 was downsied, de-powered and made more fuel efficent and emmission happy then compared to the 500 that came form before it... so performance was on a steady path down.... by 1990, performance started to pick back up, so they used the 305 and 350..... so on one side you have a car with an engine that has a steady performance drop, and on the otherside, and engine with a steady performance boost..... really, if more power wan'ts the issue, then I am sure GM would have stuck with the Olds 307 for 2 more years.... the the fact that despite all that, the 425 was on a trend to decrease performance while the 350 was on a trend to increase performance speaks about its power as well.

Would I never own a '90-'92 350 brougham? of course not, I think they are very nice cars, and given the era, it was a fitting engine. If I had a 350 Brougham, would I swap a 500 in? honestly... probably not, I would just work with the 350.... but idealy, yeah, I'd want a 500..... there is something about big block Cads that are so different then any other engine.... from the way they look, their made, how they run, what they can do, how to build one up and everything.

Just think if they kept the 425 around until 1991, back when performance was coming back..what kinda power that would have made?! A lot more than the 350 at that time. Just think... a 425 with throttle body injection and the same compression ratio as that 350.

-OR-

How about a '79 Cadillac with a '79 Chevy 350?? Weak!


And yes Rick, the LT1 is a godsend!

big block Cads would have never made it thru the years...

but if they did, like the 454 and 460... into the early 90's.... that would be pretty sweet.

'79 Seville had an (Olds?) FI 350.... smaller and lighter car, performance wasn't too bad.

seeing as how a stock 500 is putting out 300hp and 420ft-lbs of torque (real numbers) there is lots that can be done to boost the power... I woudln't really bother with the 425 in that aspect... just because at the time, they big blocks were being phased out..... but the 425 is still a great bargin.... and it did manage to get resonable fuel mileage too... 13/18mpg isn't all *that* bad considering everything.... my friends '00 Tundra gets the same exact mileage....

Oh I meant '79 deVille, but the weight is pretty much the same as the Sevilles.

If they could have kept the 425 or 500 thru the '80s and into the '90s, I doubt it would have been used in the Caddies, except mayyyybe the Brougham. They would have probably used it in the Heavy Duty trucks, but they had the 454 so they don't need another big block.

I wonder what kind of real numbers the 425 is putting out? 230hp and 350 lb/ft sounds reasonable, considering the 500 made 300/420.
And 13/18 isn't terrible nowadays when comparing it to a truck. Besides, its mechanically more like a truck than a modern car anyways.

as far as the 425's acutal power... I am not sure... I know the factory rating was a little on the low side.... tho keep in mind, it is bogged down.... atleast she dosn't have an AIR pump, that was good.

its hard to say without ever putting it on a dyno..... it wasn't about the HP tho, it was all torque. When my father had his '79 Coupe DeVille, he towed the boat with that..... 18' Sea Ray, Ford 302, 5,000lbs w/ trailer.... and that car would tow the boat and drive down the road like there was nothing even there.... until getting it was time to get it out of the water.... open rear end and no 4WD... and trying to pull a good sized boat out of the water means the boat ramp became a burnout pit.... I remember the days when he was messing around (knew the owners well) and would go to pull it out... he would just floor it and both tires would spin ( ramp was wet) and the speedo would get burried at 85.... ahhh good times....

But, that car would pull the boat a whole lot better (on the roads and stuff) then the '85 Bronco 351HO 4bbl, towing package.

When I had the complete Northstar in the trunk, full tank of gas and 3 other friends in the car... it still drove around like nothing was going on (rode a little low tho)

Lets keep in mind shes got 8.2:1 compression, is almost the smallest, least powerful big block Cad.... in a time when the industry was moving from gas guzzling beasts to smaller more fuel efficent engines.... meaning, the enigne had alot of smog control devices, all very early systems so it wasn't really made to work with it well...

The 425 isn't some magical engine in itself... but it holds its own, and its got lots and lots of potential as well. Personally, IMO, the big block Cads are the best gasoline V8's made.... thats just how I feel, I personally never gave much thought into the Chevy enignes.... you just see them all over... how many 350's can you look at, at a car show before one becomes like the last? For that reason I am always looking at the oddbals... Caddy V8's if there are any... Olds etc... even the stright 6's, slant 6's etc.... I get tired of seeing the same thing. I also don't think a SBC should be in a fullsize Cad... the only exception being the '93-'96 Fleet, with the LT1... and even then, it was the only engine at the time worty of being used in that configuration...

Gotta realize that the 425 and the 350 were serving 2 different purposes... the 425 was downsied, de-powered and made more fuel efficent and emmission happy then compared to the 500 that came form before it... so performance was on a steady path down.... by 1990, performance started to pick back up, so they used the 305 and 350..... so on one side you have a car with an engine that has a steady performance drop, and on the otherside, and engine with a steady performance boost..... really, if more power wan'ts the issue, then I am sure GM would have stuck with the Olds 307 for 2 more years.... the the fact that despite all that, the 425 was on a trend to decrease performance while the 350 was on a trend to increase performance speaks about its power as well.

Would I never own a '90-'92 350 brougham? of course not, I think they are very nice cars, and given the era, it was a fitting engine. If I had a 350 Brougham, would I swap a 500 in? honestly... probably not, I would just work with the 350.... but idealy, yeah, I'd want a 500..... there is something about big block Cads that are so different then any other engine.... from the way they look, their made, how they run, what they can do, how to build one up and everything.

I certainly can't disagree with you on thinking that any other engine than a Cadillac belongs in a Cadillac, whether it be Chevy or Olds. However, since there wasn't much Cadillac was doing engine-wise before the N* arrived, I took the best thing I could get, and I'm happy to have it. I'm a big Chevy guy, because I've seen alot of them, I learned everything I know about engines from them, and I think they're easy to work on, easy to fix, and very easy to modify.

I think it's pretty cool to have an interest in big block Caddies, I just haven't caught the bug yet because a motor swap is quite a bit more work than a cam swap. However, the big block Caddies really are works of art; all that nickel in the block, the massive stroke and bore, the ability to run forever, etc.

I certainly can't disagree with you on thinking that any other engine than a Cadillac belongs in a Cadillac, whether it be Chevy or Olds. However, since there wasn't much Cadillac was doing engine-wise before the N* arrived, I took the best thing I could get, and I'm happy to have it. I'm a big Chevy guy, because I've seen alot of them, I learned everything I know about engines from them, and I think they're easy to work on, easy to fix, and very easy to modify.

I think it's pretty cool to have an interest in big block Caddies, I just haven't caught the bug yet because a motor swap is quite a bit more work than a cam swap. However, the big block Caddies really are works of art; all that nickel in the block, the massive stroke and bore, the ability to run forever, etc.

I agree, given what your options were, you picked the best one.

Cadillac was doing alot before the Northstar... they had the 4.x series... except for the HT4100 tho, they were FWD-only.... with the Brougham being the only RWD Caddy left.... GM was sticking whatever was in the parts in in them. I think the 350/LT1 combo was a good exit plan for the RWD chassis... plus, it was just natural as it followed the other cars it shared chassis with.

They were doing alot, but they were definately suffering from "Roger Smith" syndrome. The 4.5 and 4.9 are pretty darn good motors, good torque and decent HP, but it's engines like the N* that a luxury brand like Cadillac should have been building since the end of the big block. Hell, the fact you could still get a carbureted engine in a 5.0 '90 Brougham is pretty sad, considering what BMW, MB, and the like were doing at the time.

Shit, i mean as long as they were throwing in Chevy engines, why not the 454?? Give it some power not seen since about 1971!

Well, the Brougham was marketed to a much different community then a BMW.... I personally like the carburator....

But, the Brougham, while the top luxury model for Cadillac, wasn't the top performance or tech model.

The 4.x series *was* a leap in advancement.... HT means High Technology... and IMO, they were great powerplants for Cadillac in the 80's.... it did exactly what it was made to do and performed quite well... back in 1991 when the 4.9 came out, they were one of the fastest FWD cars on the market.... then the Northstar picked up in the 90's and carried on until today...

Really, Cadillac has always been either leading, or just as good as the competation in the power/performance department... I would say the only real drop would be 1980-1987.... the gap between the 425 and the 4.5.... the 425 in the '79 chassis held its own for what it was, as did the FWD 4.5 (even TBI) Once the 4.9 came along, it brought new life into the older chassis... then when the Northstar came along in 1993, it put Cadillac nearly at the top ITO performance.

Then with the RWD cars... the 350 did its share in keeping them competing with the Town Car and.... well, that was it... then when the LT1 came along.... it was all over there.

Actually in 1994/1995, Cadillac had a very neat lineup.... the 4.9, the Northstar in both the LD8 and L37 versions, and the LT1...... thats a pretty nice engine lineup if you ask me :).

Shit, i mean as long as they were throwing in Chevy engines, why not the 454?? Give it some power not seen since about 1971!

cause the origanal cliantel would have nearly had a heart atack when they decided to push their luck and run an Olds 307 wide open.... they would probably break a hip when shifting a 454 from Park to Drive...lol...

Plus, I think fuel economey was kinda important at the time too....

245hp and 355 lb/ft baby!!!

Ben, so how IS the 425? Did it meet your expectations?

It is very nice, it has that beasty feel, its just really strong. mine kinda needs a tune up, but it still runs great. Today I played around with an old hot rod '60s GTO, and the 425 kept up just fine. and now I know why Rick is always talking about nailing it at 30 and holding on.. wow, I didn't know a 4,000 pound car could do that! I'm in love.

Nice!

gut the cat (drain the beads) get a modified '68 472 intake manifold on there and a hi-flow air intake... rebuild the car... and she'll be cookin' nice.... add some 500 exhaust manifolds and a worthy exhaust system, and that would really open it up.... manage to put even a mild cam on it, and the 425 would fee like a new engine.

Vroom Vroom! too bad I suck at engine work. I think maby the carb needs a little adjustment, the first time I back out of the driveway in the morning, it stalls, then the rest of the day it runs fine. I'll see what its like after a tune up and go from there.

It is very nice, it has that beasty feel, its just really strong. mine kinda needs a tune up, but it still runs great. Today I played around with an old hot rod '60s GTO, and the 425 kept up just fine. and now I know why Rick is always talking about nailing it at 30 and holding on.. wow, I didn't know a 4,000 pound car could do that! I'm in love.

Cool! What speeds were you guys messing around at?

We only got up to around 65-70... in a 35 zone. my friend Charlie was flipping out.

Vroom Vroom! too bad I suck at engine work. I think maby the carb needs a little adjustment, the first time I back out of the driveway in the morning, it stalls, then the rest of the day it runs fine. I'll see what its like after a tune up and go from there.

Yeah, the choke... only when its cold... after we rebuilt mine, the choke still needed to be adjusted... she wouldn't want to stay running when in gear at idle on a cold start... I remember backer her our and it nearly stalling... the RPM went down to 200RPM, the low oil pressure and charge lights came on, I would be feathering the gas, and she would pick back up.... keeping a 7.0L big block running at 200RPM was fun.... never did get to adjust that choke.

is that easy to adjust, or cheap to have done? its sort of annoying to back out of the driveway, and have the thing stall with the kid next door looking at it like "what a hooptie" I want to race him.

The choke is electric... so there isn't a classic adjustment on it that I know of, I know it can kinda be set durring a rebuild....

there are two things you can do... first, let her warm up for a few minutes... its not fuel injection, they will need to warm up when cold..

or... as what I did, learn the drive it when cold using both feet, feather the gas and keep the RPM up using the throttle and use the brake to control speed while backing up.... it was fun and sound cool too ;) :).

Ok, I tryed leting it worm up for a lil bit today and it worked fine, I guess it just wants to wake up for a second lol.

see :)

Can't use fuel injection thoughts with a carb, or carb thoughts with fuel injection (ever see someone pumping the gas on a FI car to start it? oor in the movies when an engine stalls and they are pumping the gas? I chuckle at it)

good rule of thumb.... you've got 2 idle speeds (for this purpose) the normal idle, around 550RPM and the high idle, around 800RPM.

the car is NOT made to put put into gear when sitting at high idle... just not good for the trans, tho it really wont bother the TH400.

Well, o na cold start, it'll go to high idle, after a minute, hit the gas a little, the idle should go down (kick down) to the normal idle... if not, it'll stay at the iher idle, in that case, wait a little longer, then hit the throttle again and see if she'll kick down...

I found out that once it kicks down, its warmed up enough where it wont stall... so I'd reccomend that. Once we rebuilt the carb tho, she still would sometimes want to stall out after the kick down... but I was used to that.

Of course, more then a few times, for one point or another, I needed to make a quick run in the Caddy, so I'd hop in start it up and be gone.... that was always fun... usually would backfire a couple times.

I miss the 425.... it was so much more...... "engine" then newer cars... the computer and FI masks everything, the 425 was so cool for the fact that I could really learn the engine well, it could manage to idle at 200RPM if you were good, and it just felt like an actual engine... newer cars feel more like a propulsion device then a hearty engine under the hood.

[QUOTE=I~LUV~Caddys8792]
If they could have kept the 425 or 500 thru the '80s and into the '90s, I doubt it would have been used in the Caddies, except mayyyybe the Brougham. They would have probably used it in the Heavy Duty trucks, but they had the 454 so they don't need another big block.
QUOTE]

Heavy duty trucks.....hmmm...like a 500 in an Escalade! :thumbsup:

Just bought a 78 DeVille Sedan with a 425 (carb).
Is there anyone who can tell me a that I took the wrong choice?
Are there any weak points to be aware off?
Any hints I should take in consideration?
Many thanks in advance for a few comments. :-)

Just bought a 78 DeVille Sedan with a 425 (carb).
Is there anyone who can tell me a that I took the wrong choice?
Are there any weak points to be aware off?
Any hints I should take in consideration?
Many thanks in advance for a few comments. :-)

Those aren't the questions to ask AFTER you buy a car! :) Those cars are some of the most reliable ever made, so you made a good choice. Weak areas are rust, so check the rear frame around the wheel wells. Other than that, they are pretty solid cars. The interior plastics are another not so sturdy part, and replacements are hard to find.

Thanks a lot that you approved my decision.

Another dump question: How often do you recommend to change auto trans oil and filter change for the TH400 ?
I read between 1.000 and 20.000 miles.....

Thanks a lot that you approved my decision.

Another dump question: How often do you recommend to change auto trans oil and filter change for the TH400 ?
I read between 1.000 and 20.000 miles.....

Wow, where did you read 1,000 mile tran oil change? That's a waste of money and oil!
I wouldn't change it any sooner than every 30,000 miles unless you drive it hard.

I meant 10.000...my mistake, sorry.

Thank you for the information.

Does anyone know, what is the highest known mileage/lifetime of a 425?

Does anyone know, what is the highest known mileage/lifetime of a 425?

I've heard of one that had over 600,000 miles.

hopefully my 79 H&E hot rod project will provide some information about the true potential of the 425 BB. check out this thread:

http://www.cadillacforums.com/forums/500-472-425-368/135876-425-project-underway.html#post1464241

so far the 74,000k engine has been pulled and expected, cleaned and painted, MTS #5 cam swap completed, heads completely redone and ported, new valves, springs, lifters, etc., 472 intake installed, carb rebuilt, timing advanced, improved stall converter, b&m shift kit. next step is bolting up the mts 425 headers and converting to a custom dual exhaust with flowmaster 40s. we're trying to get a hold of a rear end that will bolt up and accomodate some higher numerical gears. then we'll start her up and get her tuned.

this is essentially an effort de-smog the engine, and take out the emissions-imposed bottlenecks in the hopes of turning the 425 into something closer to what a big block should be.