Thread: Cadillac Compression Ratio

Tweet

The 1952 Cadillac 331 was rated at 180 horsepower with a 7.5:1 compression ratio. Would raising the CR to 10:1 bring you near 300 horsepower?

If you raise the compression you will have to bump up a few other things to get the benefit from raising it. Like a good intake with about a 650 double pumper, headers, and a good port job to the heads. If those stock heads would even work well with a good port job.

I doubt that it would make 200 with just the CR bumped up.

Is there really anything that can be done to this engine which would produce genuinely respectable performance numbers, by today's standards? According to one source I have read, the 331 shares parts with the 327 chevrolet.

This motor will respond to the same changes as any other OHV motor. The problem is that there are no off-the-shelf parts like there are for the more popular motors. If you're going to use this motor regardless, then possibly the best way to increase power by 40-60% would be with forced induction (centrifugal supercharger/blower/turbo(s). There will be a limit to the power/rpm's the motor will tolerate, with the weak link being the valvetrain, pistons, rods, crank or the main bearing webbing in the block. One or more of these will lay down on you at some point in your quest for more power.

As a point of interest, the engine in Norm Grabowskis T bucket was reportedly from his Dad's '52 Caddy. He somehow convinced his Pop that the engine was in need of a replacement, and he ended up with the old motor.

These Caddys were real powerhouses in their day. Guys like Bill Frick pioneered the Fordillac cars, where he swapped various Caddys into early '50's Fords. They made real screamers of those Fords. In the '50's the two engines most often swapped were the Caddy and Olds engines. Chryslers were popular, but large, and Buicks were just starting to appear, and the sbc didn't come out until '55.

300 hp is possible, but it will take some doing and some money. Most of it will be spent inside the engine doing stuff like balancing, boring, higher compression pistons, a good cam, and some SERIOUS head work. As Richard mentioned, parts availability will be not as good as more popular engines, however, I bought a lot of stuff from Egge Machine when I built the 394 in my Dodge truck. I think Mondello is also a source and can probably tell you how feasible it is to attempt this.

I wouldn't be too hung up on what hp you end up with, I would just do the normal hot rod tricks to the point your wallet starts to scream, and see how you like the way it runs. If you still want more go, break out another credit card.

Don

Originally Posted by Itoldyouso

As a point of interest, the engine in Norm Grabowskis T bucket was reportedly from his Dad's '52 Caddy. He somehow convinced his Pop that the engine was in need of a replacement, and he ended up with the old motor.

These Caddys were real powerhouses in their day. Guys like Bill Frick pioneered the Fordillac cars, where he swapped various Caddys into early '50's Fords. They made real screamers of those Fords. In the '50's the two engines most often swapped were the Caddy and Olds engines. Chryslers were popular, but large, and Buicks were just starting to appear, and the sbc didn't come out until '55.

300 hp is possible, but it will take some doing and some money. Most of it will be spent inside the engine doing stuff like balancing, boring, higher compression pistons, a good cam, and some SERIOUS head work. As Richard mentioned, parts availability will be not as good as more popular engines, however, I bought a lot of stuff from Egge Machine when I built the 394 in my Dodge truck. I think Mondello is also a source and can probably tell you how feasible it is to attempt this.

I wouldn't be too hung up on what hp you end up with, I would just do the normal hot rod tricks to the point your wallet starts to scream, and see how you like the way it runs. If you still want more go, break out another credit card.

Don

Haha!

The reason I ask is because of a certain 1956 Cadillac advertised with the engine for $8,000 and wanted to know if the car/engine combination was worth it for my purposes before laying out serious cash. I'm just not sure it wouldn't be more cost effective to go the route of a newer small block.

You guys sure know your stuff!

Originally Posted by Maxb49

Is there really anything that can be done to this engine which would produce genuinely respectable performance numbers, by today's standards? According to one source I have read, the 331 shares parts with the 327 chevrolet.

I suspect that the only thing shared by both these motors is that they're both made of cast iron.

If a guy wanted to keep it all Cadillac, he might look into transplanting a '68 to '76 Cadillac 472 or 500 cubic inch motor complete with TH400 auto trans or even adapt a later 700R4 behind the motor for the 4th overdrive gear. Anything and everything is available for these motors, including aluminum cylinder heads.
http://www.crankshaftcoalition.com/w...gine_Knowledge
http://www.crankshaftcoalition.com/w...e_500_Cadillac
http://www.500cid.com/
http://www.cad500parts.com/
http://www.cadillacperformanceparts.com/