425 vs. 500..... hot-rodding.... need some opinions...
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500, 472, 425, 368 Discussion, 425 vs. 500..... hot-rodding.... need some opinions... in Cadillac Engine Technical Discussion; Hello everyone... it has been a long time since I was last on here.... as everyone knows I have the ...
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    425 vs. 500..... hot-rodding.... need some opinions...

    Hello everyone... it has been a long time since I was last on here.... as everyone knows I have the '93 Coupe DeVille (my baby) and my 1989 Oldsmobile Delta 88 (winter/2nd car) I am going to see about being able to have both of those on the road.... gotta check it out next week....

    ...anyway, this topic has to do with my *other* car... I do not know if I told everyone about it.. I think I did... it is a 1979 Sedan DeVille d'Elegance...

    Now, I got the car super-cheap becuase the guy thought it had a blown engine... it sat for 5 months and the wrist pins froze up... after driving 3miles to the gas station, the engine was quiet as ever....

    Anyway, the car has 85k miles on it (origanal... I have some service recipts, origanal window sticker and 8-track tape still in shrink wrap) the whole drivetrain is solid too....

    for what it is, the car has alot of power... it is not fast.. but it does have the power (2 30 foot lines of rubber on the ground proves that) but I want to make a sleeper out of this... something that you look at, and it looks like an old Cadillac, but will beat much faster, sportier cars.....

    Origannaly I had it thought out, get a 500, get it rebuilt with performance in mind, throw some hot rod parts on it, and be done... well, I can get a complete 500 for $100, ready to be rebuilt.... we are very close friends with the owner of a machine shop, so labor will be very cheap, if anything.... I would get a stock rebuild done, but get the heads shaved down to bring compression up and a valve job, we would throw in a performance cam, the Edelbrock intake manifold, then exit with stock exhaust manifolds running to true dual exhaust system....

    that *was* the plan... the way I figured it out, it would be under $1,000 total and I would have a '79 DeVille that would run a low-mid 14 in the 1/4.....

    Well.... funds are tight for me right now.... well, not really tight, but I don't have $1,000 laying around..... plus, at 17, I am paying high insurance premiums, and I would like to have 2 cars insured (the Oldsmobile) and I will have to renew my insurnace plan next month, so I am trying to ave as as much cash as possible to pay off a big chunk of my insurance.... so I have 2 options....

    hold the 500 plan off until the winter... hopefully if I work alot, and make money, I will not have much to spend it on over the winter (yeah right) and then build the 500....

    OR.....

    something I recently thought about.... build up my 425.... what's going for it? well, it would be the origanal engine in the car, only 85k miles.... the engines runs great and has no problems either.... although when I remove the oil cap and look into the valve covers, both the rocker arms and oil cap are sludgey.... oil changes probably were not done on time in its past life... but it dosn't seem to hold it back..... if I kept the 425, I would put the performance cam in, the edelbrock intake manifold (I heard those are the 2 biggest things holding the BB Cads back) get the carb rebuilt, keep the Qudra-jet, but get it rebuilt (it needs it either way) and then exit with the true dual exhaust.... *maybe* if we were in the mood, pull the heads and have then shaved down and do a valve job (can't do much with 8.2:1 compresson)

    Now with this idea.... I wouldn't be able to beat a Mustang GT.... but I was thinking a 1/4 time of low 15... which is actually very respectable for any classic luxury car... not only that, but it would surprise plenty of people at both the track and on the street.... it would be a fun budget build too....

    So, I was wondering how well a 425 would perform with the above mods... that would probabbly be $500-$600.... which is much more realistic... sure I woudln't be able to say I have 500 cubic inches under the hood, or 8.2L or the biggest production engine ever made... but I can just say it has the origanal Cadillac V8

    Well, anyone that knows my posts, knows I sure like to type alot... this post is no different... I hope it didn't scare anyone away

    for the count, I don't street race... I go to the track... the best time I have got so far was a 15.9 @ 85mph in the '93 Coupe DeVille (4.9) that was before the tune-up, and I think the cat-conv is clogged (getting that fixed soon) I went with a Grand Am club, and my DeVille is even with a new Grand Am GT (175hp 3400 V6) but I am very much into cars, same with my father, and know alot about them... which is also why I know about the 1/4 times... and why I think some of those numbers are realistic for that car....

    ...So I guess to sum it up, basically, which would be better considering my budget, the 500 build up or the refresh on the 425.... and how does the 425 take to mods?

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    after I got the '79 I took the '93 off the road, I drove the '79 around for about 2 weeks.... ran amazing... we did a very basic tune-up.... air filter, fuel filter, change the spark plugs (regular AC Delco) although the wires, cap + rotor were left alone (they are not origanal wires though) and I ran some carb cleaner.... although the carb does need to be rebuilt.... oh yeah, I tightened up the alternator belt becuase it was squeeking.. that freed up about 10 ponies (ok, jk ) Anyway, I put a total of 1k miles on the car... the biggest thing was the millage.... now I am not one to complain about gas prices.... but $50/weekto go 220 miles was getting bad (12mpg around town.... I think like 18 on the highway).... not only that, but I was driving the '79 while gas prices were at the peak... $2.33/gal for premium (what I run in all my cars) now it is about $2.23/gal for premium....

    this car is just going to be a fun cruiser in the summer.... not a perfet restored car.. which is why I do not care that the crappy fake-wood contact paper on the door handels peeled off, the dash is cracked or that the millage sucks.... when I drive the '79 I drive for the power and enjoyment of what it is, and don't care at all about the gas that the big girl desires

    Plus for gearing, right now it has the stock 2.28.... I would like to find a 2.78 posi for it.. but that will be difficult.... the TH400 is going to stay, it will get a shift kit though, and a tranny cooler.... I think that about covers it for now...

    * actually the guy has 2 500's..... $100 each, they are both complete, although have been sitting in his warehouse for 15years, they are not turn-key and go... they need to be rebuilt... prefect cores.... once I decide what to do, I want to get the numbers from the engines and see which is the better choice to go with...

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...


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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    500. Wait another six months if you have to.

    You can buy all the performance parts in the world for the existing engine and make it run like a scaled dog but every time you run it that little voice is going to be in the back of your head saying "yeah but what if I had done the 500?".

    Trust me on this one... I've bought several cars that were almost what I wanted but not really. Like the '73 AND '74 SDV when I really wanted another '70. I ended up selling them both because of that little voice.

    Steve B.

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    So... many... words...

    It's a tough call. I've got a 78 Fleetwood with the 425, but my 425 is at 180k and not in good shape, so I'll go with a 500/472 if I do anything to this car performance wise. Your 425 is probably in good shape, which makes the choice tougher. At .6hp/ci, which is pretty much stock, you'll get 45 more hp with the 500. I'd probably save up and go with a 500. That way you can be sure the 500's in great condition before you start modifying it. The 425 has a minor issue with a weaker crank than the 500, but unless you're running lots of nitrous or something it's not a big deal. Speaking of which, you might consider nitrous as a mod later on, I wouldn't try more than a 125 shot on a 425, but I'd be comfortable with more like 150-200 on a 500.

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    For 100 bucks a pop, I'd buy both those 500s. They don't make them any more you know? Seriously though, they shaved a lot of weight off the 425 crank to lighten it. Plus they were just kinda de-tuned in general. You never know, just because those 500s have been sitting doesn't meen they need rebuilding. You may just need some valve seals and such. As long as they aren't full of sludge or rust, after all it's just a fun car right?

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    Quote Originally Posted by Night Wolf

    for what it is, the car has alot of power... it is not fast.. but it does have the power (2 30 foot lines of rubber on the ground proves that) but I want to make a sleeper out of this... something that you look at, and it looks like an old Cadillac, but will beat much faster, sportier cars.....
    Really? I wouldnt expect that from car with 180 HP.

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    I have been thinking about it more...... and I know I really want the 500... just like how i first wanted to do the 500 build on a '75/'76 Fleetwood or DeVIlle (Coupe) but not only did I get a crazy deal on my '79, it the '75/'76 weigh an extra 1,000lbs+ then my already beefy '79.... with all that weight, it is just hard to make the thing go fast....

    ... something my father mentioned... which I will ask the guy next time, if he wants $100 each, maybe offer $150 for both and see what he says....

    ...my 425 runs great, I ran it today for a bit... and yesterday... when it sits for a week or so, it takes a little while to get her running... but it is carburated, and once it runs (besides the hesitation when cold.... carb needs rebuilding) it runs great....

    ... I am pretty sure the engines need rebuilding... the guy even said so... they have been sitting inside the warehouse for 15years, all the oil is probably drained, and for what it woudl cost me, a fresh rebuild with some tweaks would be the smart idea....

    ... right now I am thinking, save up my money for insurance (that way I can have the '93 and my Oldsmobile on the road) then this winter, when insurance isn't as big of a deal,and I have some cash laying around.... build up the 500.... then in the Spring, drop it in and have some fun....

    plus, I would much rather say I have 500 cubic inches or 8.2L then 425 or 7.0.... its great to mess around with the ricer kids like that

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    Quote Originally Posted by JTraik
    Really? I wouldnt expect that from car with 180 HP.
    Its not the HP its the torque

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    this was when making a turn, I just stomped on the gas... although this time, I let off the gas right before the upshift into 2nd, so they COULD have been longer....

    this is with a stock chocked engine, stock tranny stock car, 2.28 rear, no posi, and a carb that could use a rebuilding.... plus a full tank of gas (about 160lbs extra in the back)

    *also in these pics, there are 2 or 3 seperate times from me...









    in the pics it dosn't look long, but in person, it was....

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    Quote Originally Posted by 67SupRFlyCoupe
    Its not the HP its the torque
    Whens the last time you saw a dumptruck do a burnout?

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    hmm, I guess it dosn't shoe the pics (I did the IMG tag) so you gotta click the link....

    ...anyway, after that, determined what she could do.... a few days latter I decided to keep my foot to the floor.... it was peg legged, I will say that much, but watching the speedo as it passed 50, I knew 2nd gear was coming, and thought to myself that it was the end of the fun.... to my surprise with the upshift into 2nd, not only did the right tire countinue to spin, but the left tire actually left rubber as well.... completly amazed I kept my floor planted to the floor.... the speedo was passing 80 (car was only moving 30mph?) and I knew 3rd was coming up.... with a 1:1 ratio in 3rd and a 2.28 out back, I knew that this had to be it... but when she shifted into 3rd, she kept laying rubber... I don't remember though it it finally didn't have the power, or I let off the gas at that time to slow down for the sharp blind turn coming up.... but I will say that in person, I couldn't believe how long it was... I think I counted 70 regular foot steps (not feet, foot steps) and the rubber was literally on the ground... I can prove that by taking about 4mintutes to circle around, park my car on the side of the road, get out, walk to the end of the lines with my camera, and as I was walking back taking a movie, I stepped on the rubber on the gorund, and my shoe started sticking to the ground... when I looked, the rubber on the ground was still in liquid form, and stuck to my shoe which picked up little pebbles and stuff....

    this is also the reason why I need posi with the engine build up....

    number 33 shows where the left tire spun when it shifted into 2nd... the only reason that I could come up with is that the engine RPM was closer to peak torque.... 320ft lbs at 2000rpm, and therefore sent a surge of power through the driveline...

    my wheels are 15" spokes and I don't remember the brand of tires... nothing popular... but the tread isn't the best... actually that is why I didn't do that anymore.... when I get new tires I'll be sure to melt the old ones down somewhere....

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    Quote Originally Posted by JTraik
    Whens the last time you saw a dumptruck do a burnout?
    when is the last time you saw a dumptruck haul 8,000lbs of gravel... uphill.... they *only* have 400hp.... a Corvette has 400hp... and you see Corvettes haul 8,000lbs of gravel around....oh wait.....never mind....

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    Quote Originally Posted by JTraik
    Whens the last time you saw a dumptruck do a burnout?
    When was the last time you seen a dump truck with car gears, car trans, car tires.........

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    Re: 425 vs. 500..... hot-rodding.... need some opinions...

    The $300 beast..... simply put, the guy thought the engine was blown (wasn't) and he was tired of seeing it around.... car is a d'Elegance (oh so comfortable) has decent options (no twilight sentinal and auto-load-level though) and becuase it was a FL. car, there is no rust (except for left back door where we think it was hit at one time... some paint peeled, and there is slight rust...)

    when I got the car it had steelies on with worn, mis-matched tires, these nice (real) spoked wheels and white walls came on my mothers '89 Brougham.... she didn't like them, so they were istting under our deck for a few years, so I cleaned them up and put them on... made a world of a difference....

    when I have more time, I'll post more about it (I don't believe I ever did here) but I have to get up in 5 hours to work for 8 hours...

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