VCCA Home Forums TECHNICAL - 1945 AND NEWER 1955-1957 Power Pack Heads

There was a topic a few days ago about PP heads. Without butting into those questions I'm interested in ID ing these heads. Supposed to be 283 PP heads. Casting numbers [both heads same number]

Huh?

Some P.P head casting numbers.
!956-3725306 (small port)
1956-Dual 4 barrel-3731262
1957-3731539 and 3740997
1958-3748770
1959-3760116 or 3755550

Huh! is right. Listing casting numbers would probably help. #3725306
Chevy Nut you have that number listed, small port PP heads, I don't think 283 were made in 1956 so has to be 265 CI..Is that right?
I plan on selling these heads and want to make sure what I have. Thanks

Yes, they are 1956 with 4 barrel only and have the small 1955-56 intake ports.

While not number correct they would raise the 1955 compresion ratio from 8.5 to 1 to 9.25 to 1 also.

The xxxx306 heads were also used with the 220 hp early dual 4 bbl engines. First ~700 '56 Corvettes and an unknown number of passenger cars used them along with xxxx225 intake, two stud ramshorn manifolds, oil pan with dip stick, 9-fin valve covers without cutout.

I think you mean 1956 225 HP dual 4 bbl. engines.

The 220 HP engine came out in 1957 -was a power pack single 4 barrel.

Oops,
I was going from memory on the 220 hp. Gene is correct the early '56 2-4 bbl with cast # 3728725 intake is indeed factory rated 225 hp. The later 2-4 bbl with large port cast # 3731762 heads and 3731394 intake is 240 hp. Sorry my fingers hit the wrong keys.

Chip...........You lost me here

There were three horse power Corvette engines in 1956.

210 HP base engine.Single 4 barrel and solid lifter 3711354 camshaft.Was same engine as 205 HP power pac car engine but with solid lifter camshaft.Small port heads and intake,dual point dist.

225 HP dual 4 bbl engine RPO 469,dual 4 bbl's.3711354 cam as above,polished light valves,large port heads and intake,dual point distributor.Did have an early and late design Carter 4 bbl. carbs. but of same demensions.

240 HP dual 4 bbl engine RPO#449.Had high lift cam shaft #3734077-was the first Duntov cam....rather rough idle ,made just for racing.Used for both stock car (NASCAR) and road racing.Seldom advertised.

The 3711354 was also the "racing cam" in 1955 and stock Corvette cam for that year-raised HP from 180 to 195.

I see no mention of small port heads or manifold or intake gaskets in parts book for dual 4 bbl engine.I sold a great amount of over-the counter hi-performance parts back the due to my assoiation with drag racing and do not recall it.The parts book lists nothing as to first design-second design etc.......The 392 intake and 764 heads are the only ones I see listed.
I am curious as to where you found the information. :confused: :confused: