LS5 open chamber heads

[Z28SSMAN]

Here's a pic of one of the original heads from my '71 454 LS5. This is how they dropped the compression to 8.5-1. They opened up the head chamber and used a flat top piston with two valve reliefs.

https://imgur.com/w1bKjiZ

https://imgur.com/R5Jhbxs

[MR.hp]

One thing, I am surprised that Chevy would have used those heads on a 71 454 as they are the same heads use on 256hp 396's back in 1969. There are 2 good things about those heads, 1. the exhaust valve is very unshrouded, 2. the CC's are 113 on those heads. Those castings also have a very high port floor also on the exhaust. Not a bad head and the 781 and 049's will make more HP but have bigger chambers.

[Z28SSMAN]

Interesting. If these are 113cc, then 781 and 049s are bigger yet?