[MARKDTN]

Originally Posted by ghackett1

Thx, but if he has 487 heads he does not have 11:1 compression with 76cc heads, basically the same foundation as the 72. 1970 had 64cc heads and 11:1 compression with the LT1 either corvette or Z28. The difference lies there. Basically the 71& 72 were the same. Also in 72 they changed how they rated the hp from the crankshaft to the rear wheels so the 72 numbers looked much lower but were basically the same as 71.

Here are the head specs for 71 & 72 Z28: 3973487 comes up as s good for '71 or '72 Z/28 head at 2.02/1,6 valves and a 75.47 cc chamber.

OK. Sorry. '71-72 LT1 has 9:1 where '70 was 11:1. But my point was that the OP does not have an LT1 foundation to build on. Not that you can't reliably get 300HP+ out of a 2-bolt cast crank 350 but I was just pointing out that the LT1 4-bolt bottom end is quite different than a Biscayne 350 2-bbl short block even though the block casting number is the same. And as you point out, different cylinder heads with bigger valves are all part of the package to get more power from the LT1.