I have a 1958 Cadillac Coupe Deville, in about a million pieces. The guy I bought it from sold it to me because his teenaged son started “working” on it and took it all apart and just left it there to rust. I had to make three trips to get all the pieces, but it is at my house. I had dreams of trying to get it as original as possible, but the more I look at it the more I am realizing I should make a nice custom out of it. I want to start with the engine, the front fenders, hood, grille and bumper are off, so I figure that this will be a good place to get going. The original engine is not running and is in pretty bad shape. I think it would be best to pull the stock V8 out, save it and find a 1970’s Cadillac 472 or 500. My questions are: is this a good idea, can I use the old tranny or should I change that too, what would be the best engine (and tranny) to use?

I did a resotration on a customers 57 Caddy (basically the same car you have with single headlights), building the stock 365 and Hydro is an expensive proposition.

Personally as I like same brand engine swaps and the 58 is a heavy car, I would definatly go with your plan for a 472/500. With the amount of torque you have I would leave the engine basically stock, maybe add an alluminum intake to save a few pounds on the engine. All of the accessories (AC/PS/alt) will easily fit under the Caddy hood.

For the tranny I would use a BOP TH 400. Besides being a more modern transmission with readily available parts the electric kick down makes life a lot easier than routing a cable/rod type linkage. The Caddy will have an X frame, so you may have to dig up a short tailshaft 400 instead of the long tail shaft units that are normally found behind 472/500s.

The drum brakes on the car a large and work well (although the booster is a bit pricey to have rebuilt), othewise someplace like Willwood might be a good place to check for a Disc brake conversion.

Thanks so much for all the inormation you gave!

If your ever interested in selling the caddy let me know Thanks Karl