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11K views 39 replies 8 participants last post by  Night Wolf 
#1 ·
Well, after completing the 1,400 mile road trip from NY-FL in 2 days with my friend Chris in the '79 DeVille, I have a new love for the 425.

This car, nearly stock/origanal with 93k miles on it never missed a single beat at all...nothing.

This is also THE BEST highway car I have ever been in. I drove the whole way, simply because I never felt tired or anything.... after driving 12+ hours a day, when we got to the destination, I was like... did I just drive over 700 miles? It simply did not feel like it at all... not fatigued, uncomfortable, tired, stressed....nothing.

Even Chris, who was a passenger the whole time, simply did not feel the effects of being in a car that long, he was like, wow, it feels like we just got up and went to the store..... as we went into town to pick some things up after driving 600 miles the 2nd day.

I had the cruise set between 65-85 the whole time, I started off with saving gas in mind and got 17mpg, once we hit Georiga and North FL, I was like what the hell and kicked it up to 85....MPG went down to 15. The car is much more stable at 70/75+ then 60 or 65... dunno why, but it just feels better.... it also dosn't like to be drafting alongside or behind large trucks... I guess it needs the downforce/air resistance.

I knew gas mileage was gonna be bad... I was getting about 320 miles to a tank, and it would take about 19 gallons to fill it... all in all I spent about $240 or so on gas.... eh, whatta ya gonna do?

Chris slept alot durring the trip.... we had my iRiver MP3 player and Chris' iPod going thru the cassette deck, didn't use the FM or XM at all. Stock sound system except for Kenwood 2-way 4x6 in the front, it sound really good.

at 70, the RPM is right at 2,000...the torque peak... at 85 it was around 2,400.... out of the efficent range for the engine, and well over low drag rating for the chassis, yet there wasn't a single issue at all.

I still can't believe how amazing of a highway car it is.... I often rag on the '79 and 425 in general... but no more. Sure the '79 isn't massive like '76 and before, but I have learned to like it... just as much if not more. IMO the interior is superior then the eailer years, and on the highway, that is what counts. The 425, sure it isn't a mega-power, fast drag racer or anything, but it more then gets the job done. 28 years old, 93k miles..... a 1,400 mile trip and *NO* oil consumption at all... it was full when I left and full when I got here...amazing! and I don't drive it easy either... hell the night before we left I did a huge burnout in the Wendys parking lot... sure it was raining, but that was the point... it kinda stayed at redline for a few seconds with my foot to the floor.... that didn't bother it either.... nor did the donuts in the snow last month when I went up to NY....nor jumping it over that one hill back in NY, or taking it to the drag strip, accelerating hard, burrying the speedo in 2nd gear, crusing near 100 for about 30mins stright.... or anything else.

This car simply dosn't care... I do not beat on it though, I take great care of all my stuff, it has a full tune up and gets regular oil changes, I don't do stupid stuff either..... but for whatever reason I don't really treat the '79 as a classic, as I would say a '59 Caddy... I treat it as a sweet daily driver... I am not afraid to use it... probably because I get more enjoyment from the car when I am actually driving it and using it, then I would with it sitting in a garage somewhere.

It isn't without its faults of course... the front end needs some work, mostly the A-arm bushings are shot and need to be replaced, so I will replace everything on the front end when that time comes around. The climate control is tempermental, though the AC is now working (recharged) but I may have to clean the contacts. The new (used) washer motor is starting to be a pain with the washers not working etc.... then stuff out of my control, scratches in the paint, rips in the vinyl top, some hazey chrome, fadded interior etc....

But none of that really bothers me.... hard to explain the bond between this car and me, Actually the bond I have with each of my 3 cars are vastly different from each other.

So in closing, I will say I have a new love for the '79 and the 425, no more will I ever dog on either of them.... they serve an amazing purpose and there is great potential to be had.
 
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#3 ·
2400 rpm at 85mph....damn!
 
#5 ·
in city about 10/11mpg and open highway about 18/19 ..i just went on a vacation and did an oil change,new oil filter,new air filter,and it got great gas milage..i was amazed..and in my car its recomended that you used 10w-30..but i just got my car to finally roll over to 100,000..and im starting to use straight 30 in it now cause its a thicker oil and dosent run the oil out fast unlike 10w-30..and i think thats also maybe why im getter better gas milage
 
#7 ·
Took the 75 up to Santa Fe today, 120mi round trip. Filled up before and afterwards, calculated out to 14.4mpg, cruising at 82-84 the whole way. Did a nice burnout when I got back (was trying to get my friend to race me in his 3.8L 91 Park Ave.) The 500 sure is liking the cool air, it won't even peel them when it's hot in the summer.

Go 500! I like this motor. There's a reason I just bought 2 more of 'em (ok, one's a 472, but eventually it'll sport about 562ci anyway.)
 
#8 ·
Did you actually race your friend in the '91 Park Ave?
 
#10 ·
I~LUV~Caddys8792 said:
Did you actually race your friend in the '91 Park Ave?
Not yet. Expect a video in the kills section later this week :lildevil: (well, I might lose... I'll still post a video though.) If he brings out his 76 Lincoln that's an easy kill for the 75. 2bbl 460 is no match for a 500!

Anyway back to your regularly scheduled 425 thread.
 
#19 ·
The old rear is out (and on eBay for sale), and I'm getting some better control arms for the new rear, and hope to have it and headers installed by Spring!
Right now, I have cleaned up the whole area around the rear and I am going to paint it with POR-15. I did the engine bay and the outer part of the rear frame about 6 years ago when I installed the engine. It's still holding up good, so I'll paint where the rear end will go now. It should look nice when I'm done!
The nice thing about the Impala rear I got, besides the 3.08 gears and posi is the disc brakes! It should help slow my boat down better!
 
#20 ·
I definitly want to find how how the 425 (472?) performs with the 3.08, because that is exactly what I have been thinking about putting in my '79.

I dunno about the Impala rear, but i know rear disc brakes were optional on these cars.... and I later found out the massive drums actually did a better job at slowing the car down then the disc option.... much more contact area, and in the back heat isn't as much of a problem as the front... just something I read once.
 
#21 ·
davesdeville said:
If he brings out his 76 Lincoln that's an easy kill for the 75. 2bbl 460 is no match for a 500!
Actually IIRC, the '75 Town Coupes were like .5 second quicker in the 1/4 mile than the '75 Coupe deVilles! :shocked2: I think its a 4bbl 460 running like 208hp and 357 lb/ft of torque.
 
#22 ·
Night Wolf said:
I definitly want to find how how the 425 (472?) performs with the 3.08, because that is exactly what I have been thinking about putting in my '79.
I wonder what would happen if you put like a 4.11:1 rear end into a caddy with a 500 or 425???? :hmm:

I think it would pull like nothing else off the line, and really die at higher rpm's
 
#25 ·
I~LUV~Caddys8792 said:
I wonder what would happen if you put like a 4.11:1 rear end into a caddy with a 500 or 425???? :hmm:

I think it would pull like nothing else off the line, and really die at higher rpm's
It would be comepltly pointless.

I already get tire spin with the stock 425 and 2.28 gears.

4.11 is just insane for any BB Cad.... they simply don't need to rev like a Chevy, they like to tug.

what would happen IF?

It would probably top out 3rd gear around 70mph..... flooring it anywhere from a stop to that would probably equal massive amounts of wheel spin.... yeah it would be a huge kick in the pants, but pretty pointless after that.
 
#26 ·
interesting interesting.....
 
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