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My neighbor has a caddy eldorado with 55,000 original miles. The car body is rough, but runs like a top. He wants to sell me the car. I have seen guys on here talking about the big caddy engines before. I have a few questions:

1) Will a rear wheel drive tranny bolt up to this? ( Currently front wheel drive)

2) How many horsepower does this engine put out?

3) What is something like this worth? I don't know if I want to buy it, but if it is wothwhile I would keep for a later project. ( Even though wife wants no more projects brought home until all else are finished)

Thanks,
Rick
 

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BOPC (Buick, Olds, Pontiac, & Cadillac) transmissions are interchangeable between the brands, and don't consider anything other than a TH-400 for it or plan on replacing transmissions often.

Stock they run in the high 200 to mid 300 horsepower range, and they were very conservative about that number it's likely a bit more, but the torque is MUCH more, if I remember right my '75 500 put out 275 hp and 385 tq from the factory but that's a guess without the original specs.

They are not meant for high revs, and the valvetrain is the first thing to go when run at high rpm's, but there are replacement parts to alleviate that, as well as aluminum heads and intakes, which will lower the weight of the engine to the low side between a small and big block Chevy. Headers drop a bunch more weight too.


A problem you will find putting it in a rear wheel drive vehicle is the front sump oil pan getting the best of you, just find one from a later Caddy 368 or 425 with rear sump and get the pickup tube with it, as well as the correct dipstick, but if you can manage to do it move the dipstick to the other hole in the block to correct that little quirk too. you might also consider swapping out the oil pump (it's externally mounted and the oil filter mounts to it) there are three different ones, one points away from the crank pulley, one points forward, and one tucks under toward the bottom of the crank pulley


I've swapped a couple into RWD vehicles, and have a few parts left from a couple extras, and still have a 500 on the floor of the garage too. I also have pics of 500's swapped into both a 2wd and 4wd GM truck chassis in my photo album.
 

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The caddys are GREAT engines. No point in making them rev, and no need for OD. I agree... TH400 is the way to go. They make so much torque over a broad range of RPMs that you don't need a lot of gear to get things moving, which means you don't need OD on the highway. Many of the Caddy 500 drag racers are shifting at 4500-5000 using a 3.08 gear and still turning in low 11s.

For performance use the first thing to do is ditch that valvetrain. Shaft rocker conversions exist and that's what I did. Piston options are slim, so about your only choice is cast or custom. Cranks are plenty strong, rods seem to be above average. I built a 75 500 that made 390 hp/575 tq with a very mild cam and lots of careful head work. Idled at 450 rpms, redlined at 4500, peak torque was at diesel RPMs, absolutely roasted 255/70-16 balloons on the truck it was in with 2.73 gears, highway RPMs were about 1800 without OD. And, if you kept your foot out of it, it would reward you with 18 mpg with a carefully tuned Qjet.

As far as value, it depends. They tend to bring a little more money than SBCs, and they're pretty much on par with buying a buick or olds 455. Don't let the secret out, though or they'll start being expensive :)

Here is one I built to put in my 66 Pontiac Bonneville:
 

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Buy it if you can afford it.
It can be made to work on rwd.

Most people don't realize that an all iron 500 Caddy is only 90 pounds heavier than an all iron 350 Chevy. apples to apples.
Just installing an alum intake on the Caddy cuts off more than 40 pounds alone.

These things make great monsters when the entire front drive train is mounted into the bed of an old Chevy LUV pickup.

Actually it takes a big chunk of railroad rail under the bumper to keep the front wheels down (most of the time). LOL :thumbup:
 

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Discussion Starter · #6 ·
Thanks for the feedback. I have been away from my computer for a couple of days.
Are aftermarket intakes etc. readily available? Or are the the same as Chevy? Same with heads? If I do anything with it, I would try to keep it lo buck. I am already almost "project poor"
Thanks,
Rick
 

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choirboy said:
Thanks for the feedback. I have been away from my computer for a couple of days.
Are aftermarket intakes etc. readily available? Or are the the same as Chevy? Same with heads? If I do anything with it, I would try to keep it lo buck. I am already almost "project poor"
Thanks,
Rick
Aluminum intakes & heads are available. Not a large selection. Caddy only fitment. I think Edelbrock has intakes, Bulldog heads.
http://www.hotrod.com/techarticles/...illac_v8/bulldog_cadillac_cylinder_heads.html
 

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do a google for Cad500 and find the guy in NM that deal with those..I am putting a 472 in my rod as it has more HP and torque STOCK than a lot of the small block stuff has built..and like the guy said the weight is not all that much different..you will need the TH400 tranny to stand up to it an if you can't find a Cad the 400 the guy in NM has the adapters so you can run a th400 from a chev..

Sam
 

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500 caddy

I have a 472 running a 4 ft blade on my sawmill. lots of low end torque, Caddy's have better iron in the block. the bores last a lot longer. My son keeps wanting to trade me for a SBC but I need all that pulling power when cutting big logs. There are several caddy specialist shops. click on the tech article wiki at the top of this page. engines then caddy for a lot of good info
 
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