Locate and install some 1967-1970 cylinder heads that have factory screw-in rocker arm studs. They will have 2.11" I / 1.77" E valves and 72 CC combustion chambers for 10.5:1 CR. The problem with that is the "locate" part. All the good Pontiac heads been rebuilt to death. The best option is to purchase a new pair of Edelbrock 61599 aluminum heads. A 400 CI engine is difficult to make high HP on pump gas.
To make good power with a 400 CI Pontiac engine, it needs 10-12:1 compression ratio, a camshaft with .500" lift, 260 deg. duration and VP C-12, 108 octane racing fuel.
Last edited by MouseFink; 11-01-2012 at 12:52 PM.