Cadillac Owners Forum banner
14K views 40 replies 11 participants last post by  Shoehorn 
#1 ·
Could you fit a 70's 500ci eldorado engine in a 84 fleetwood brougham?:rolleyes:
 
#27 ·
Don't pass on a 472 either. They'll probably be easier to find and are just as good an engine.
The best way to go about it is to find a complete, running car.
1970 was the last year of the high compression motors. '71 and '72 engines were basically the same except they had different pistons which made the compression lower. Starting in '72, they changed the way they figured horsepower and torque. That's the reason for the majority of the apparent power loss.
Regardless of the year......472's and 500's are going to have alot more power than the 368 that's in the car now.
 
#29 ·
I've just gotten a super clean 80 FWB,and it's going to get the 500 treatment soon also.I don't claim to be a Caddy expert,but I put a500 in my Chevy p/u and have several other engines stripped or saved,so here's my 2 cents.ANY 500 or 472 you choose will be a big improvement,even low-comp ones.70 Eldo engines are a little tough to locate,but the pre 71 472s are some snotty MF's.The only reason I'm using a 500 is because it's low-comp and the gas thing is a factor.This job is a breeze in an 80 because the 368 is the same block,and the oil pump and pan needed are on it also.Just find a set of 425 pulleys [no air pump] to simplify that end of things and you're gonna have one cool car. :want:
 
#30 ·
OK but i want to know about other stuff, like, hooking back up the A/C, steering column and power steering assembly (pump, etc.), hooking all the electronics back up (i don't even know if the 1980 has a computer, but i assume it does) like all the "Check Engine" and "Low Oil" and "Check Oil Pressure" lights, etc.
 
#31 ·
DaveSmed said:
there was a special trans for the 81s due to the V864 setup. I believe it was some variant of a TH350 instead of a TH400. Had the same bolt pattern, would WORK, but you better baby it!
Hey wait a minute! Hold everything! :shocked2:

I did not know about this. I'm about to put a 500 in my 81 Fleetwood with the tranny from my 368.

But I still have the 76 TH400 Tranny that came with the 500. I could rebuilt it and just use the shorter tail of the other right?

How certain are you of this?
 
#32 ·
Look at the pan on the tranny that came out of the '81. If it's the same shape as the TH-400 pan, then they should be the same (or at least basically the same).
I had a site bookmarked that listed transmissions by year and body style......it looks like the page is gone now. :rolleyes2
 
#33 ·
Will do ....Thanks :D
 
#34 ·
Thank you everyone for all the sites and info. My 84 did have the 4100 but someone before me dropped a 307 olds in it which is fine if done right but it wasn't. Very sloppy. My basic goal is to put an 8.0 in sounds stubborn, this is a frame up restore so modifying mounts are not an issue. I want to keep the class and luxuary of Cadillac but also to put it one way smoke mustangs and imports, After We Are the Standard of the Industry still? Thanks again for everyones help
 
#35 ·
RWD/FWD 500cid swaps

There is some incorrect information posted in this thread, and one of the referenced web sites also has some problems.

500 cids came in Eldorados (FWD) from 1970 to 1976. They also came in RWD full size Caddys (Devilles) in 75 and 76. Whether originally in a RWD or FWD car, the transmission bolt pattern is identical, so that any 500 will bolt to any Caddy TH400 RWD transmission. I know this because I bolted up my 70 Eldo 500 to a TH400 from a 75 Deville - no problem.

FWD/Eldo 500 engines do have the following differences from RWD applications:
1. FWD starters will not work in a RWD application, but RWD starters will bolt right up to any 500 Eldo engine;
2. FWD cars did have a rear sump pan, which uses its own pickup tube, and the dipstick tube was in the rear most hole rather than the forward hole used on RWD cars - an easy swap. 425 pans/oil pickup tubes can also be used on both 472 and 500 engines, although they do require some clearancing for the 500. 368 pans will also bolt up to the 500, but a 70-76 Eldo pickup tube will have to be used and slightly modified (bent) to fit that pan.
3. I seem to recall that although the Eldo 500 exhaust manifolds will bolt up to any other 500 or 472 engine, that one or both may have a slightly different collector angle.
 
#37 ·
The special trans wasn't all THAT special.... I think the biggest change was a switch to show when it was in third gear, so the DOD setup knew when to activate.
 
#38 ·
Good , so it should stand up to my 500 then, and not have an early death.:bonkers:
 
#39 ·
If you want the most powerful big cad you can get, the best year was 1970. After that they started lowering comp ratios. Like has been said above, 68-69 not as good do to oil passages, 472 and 500's all share the same block. the statment above that the difference was bore is incorrect. The only difference is the crank which effects the stroke. The 500 was born in 1970 as a stroked 472. At that time it came in only the front drive Eldo. The blocks are all the same so if you get a 76 block you can use heads off of a 70 472 or 74 500... Biggest thing to look for is know what heads go with what piston. Al at the 500cid.com site can sell you a complete engine ready to drop in if that is what you want. These engines last for years as they had a higher nickel content which makes them hold up longer due to less wear... they are also quite lite for the amount of cubic inches they sport... You can also offset grind either crank to use big block chevy rods, which will give you even more cubic inches and better oiling. Check out the book "Big Inch Cadillac"... You can look it up on Amazon.com. It has all the info you need about this family of engines... For sake of saying it, the 425 is the newer little brother of the 472/500, only it DID have a smaller bore. I live in Arkansas and am strongly considering going around to every hunk of old caddy used as ******* yard decoration and coming back with the car for $100 down to free... That is basically how I got my first 1970 472... My dad bought a house about 15 years ago and a deville was left to rot away until I looked under the hood and woundered what the hell that thing was! Now the car is long gone and the engine is waiting for me to get back from Baghdad to build it, add bulldog aluminum intake and heads, inject it and put it in the 92 Camaro I just purchased off of ebay... :worship: I would like to thank and praise GM for producing this marvel of a motor that produces numbers with the best of them, has lower comp ratio, and still can be found for prices unheard of comparitivly...
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top