Originally Posted by PappyDan

Lets see where your going with this.
your 4.8 head has a 61.15 cc chamber and 1.89/ 1.55 valves
with a piston size of 3,779 with a stroke of 3,270 to give you
A compression of 9.49.

your 243 ls1 heads come with a 66.67 cc chamber and 2.00/ 1.55 valves
to work with a piston size of 3,893 with a stroke of 3,622 to give it
A compression of 10.19.

now the 243 heads will flow better but you increased your
chamber size on a smaller piston and a smaller stroke
That will drop your compression down close to a 9.0 or even a 8.9.
their is no cam on this world that will make up the lost power
From the lower compression on your 4.8.
Now a turbo or a supercharger would love this kind of low compression.

the best way to go is to shave 0.20 or 0.30 off of your 4.8 heads to up
Compression from 9.49 to a close 10.0.
Then add your cam for more power.

Originally Posted by PappyDan

damn it, well i was not too far off from the top of my head.
243 is LS6 not LS1 guess i need to read that book again.
thanks stew for the correction.