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Researching Caddy 500 swap into C4 Corvette; request info and pics

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I’m collecting research for a planned 500 into C4 Corvette swap. I’d like any information you have on previously done swaps including pictures.

I’ve been finding deals on C4 Vette project cars from $900 - $3500. The cost of getting a C4 is going to be less than replacing my 72 Fastback Mustang with a car of the same condition. I was going to put C4 Vette suspension under the front of the Mustang anyway, so as it turns out, building the Vette is going to be much cheaper and a little easier.

The Chevy guys in the Vette forums are advising me to stay away from 1990 up cars due to their electronics. I think I want to avoid the 84 because of the crossfire injection. I prefer using a modified TPI injection setup. I want to plumb an aftermarket Caddy intake for the injectors, install a fuel rail, build a converter box to mount where the carb would be so I can install an aftermarket 780 CFM or 1,000CFM throttle body and install a chip so that the Vette’s computer will run it as if the 500 was a factory option. (see uploaded picture for TPI adaptor box)

I know I will have issues with the tranny and the rear end. My goal for that is a race hardened Dana 44 with 3.07 gears and a race prepped Grand National TH200 – 4R. However, for this thread, the focus of my research is the physical swap of the engine and the setup and tuning of the fuel injection.

I have heard from the Chevy guys that a Big Block Chevy swap requires the frame to be notched and the rack to be moved forward 2.5”. I’m thinking with the Caddy distributor in the back, the engine can be set back a little and may reduce or eliminate the relocation of the rack. I’d like as many pictures as possible of swaps that have been done. I have also been told that I will need at least a 6 point cage in the car.

My budget (heavily affected by medical bills) will limit what I can do with the Caddy motor. My goal is to match the strength of the engine with the strongest possible modified Dana 44 rear end. However, that may limit me to a stock 500 at 10:1 with a cam, intake and headers. That would make my budget happy, anyway.

I’m not in a hurry; I am just planning right now. I want to know what to get and how to do it. I want to bargain shop at the swap meets and salvage yards and build this thing for such a cheap price that no one believes it. Paint and bodywork will be a low priority until the car is 500 powered and very fast. If I am lucky enough to find a running car, I’ll drive it while I prepare the Caddy engine, suspension and collect parts. I won’t actually begin the swap until I have everything I need; I’m not going to loose another project car to the crusher. And I am determined to show up an SCCA autocross event with the fastest car.

If you know any Caddy parts vendors who might have Corvette customers, please let them know I’m researching this swap; maybe their customers will join the forum and share their photo documentation and research data.


Cody G. Carson

Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:


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There are lots of big block Cadillac parts out there. The 472/500/425/368 was in production from 1968 through 1985 and there is a market for performance parts for all of them. The 500 was produced from 1973 through 1976. It was only in th Eldorado in 1973 and 1974 but in all of them in 1975 and 1976. The Cadillac big block is lighter than the botwie big blocks but I don't know how much a 500 weighs. These guys might help you get started:

There are lots of salvage yards that will help you with used parts such as blocks, cranks, oil pans, water pumps, etc. Do a dogpile search on "Cadillac 500 performance parts" and you will turn up all kinds of links to salvage yards and performance parts houses, most of which support big block Cadillacs.

The 500 was carbureted, although a DFI option was offered for 1975 and 1976. I would use an aftermarket dual-plane intake manifold and Holley 4160 850 cfm for the street and strip, or an Edelbrock DFI/ECM for a little more horsepower and better highway economy if you choose that route.

Here's a video showing what one guy did with a Cadillac 500 in its original body apparently an Eldorado or Coupe deVille, leaving the interior, electric windows, etc. intact. I don't know about the A/C...

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Yes, I was Jims_97_ETC before I changed cars.

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  • 1 month later...
I have heard from the Chevy guys that a Big Block Chevy swap requires the frame to be notched and the rack to be moved forward 2.5”. I’m thinking with the Caddy distributor in the back, the engine can be set back a little and may reduce or eliminate the relocation of the rack.

A Chevrolet engine has the distributor in the back but I believe the big block Cadillac engines had the distributor in the front of the engine.

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