I am planing on trying to port a set of factory heads, I have a set of 305 heads from a 79 camaro 1.7 x 1.5 valves, a set of 400 heads (493s) 1.94 x 1.6 valves and a set of 993s 1.94 x 1.5 valvesI know all of these are open chamber which are not the greatest for performance but I was wondering which is the best to work with? The heads will go on a .040 over 350 which brings up the next question with the undecked block and the 76 cc heads my compression is around 8.5 to 1 I want to be at 9.5 to 1. The only two ways I can see to increase the compression is to increase the stroke to 3.75 from 3.48, deck the block(it was just bored)or run dome pistons. The dome pistons are the cheapest option but are they the best option this is a street engine that we are trying to get 400 hp out of. Cam is a 270 magnum hydraulic, headers, 4 bbl dual plane.

 

The 305 heads will give you more compression for your 350. I would go with the dome pistons because if you play with the deck height, you will also need to change the intake manifold.