Depends on the heads. I have a set of 305 heads on a 355 and it runs hard. the heads have been machined for 2.02 and 1.60 valves. A stock set works to but look for mid 80's with a small cc. The main point being the smaller ports(intake,exhaust) will give you a boost in torque, but it will also raise your compression ratio. Don't forget to factor that in if you are,or decide to run power adders, or simply something that would cause an increase in your engine timing, because you run the risk of detonation.
does anyone know the torque for cast iron exhasut on aulm heads ..small Chevy
No such thing as a DE-TORQUE pattern.Just remove the bolts from the heads from front to back.
60 foot pounds
Heads Torque at 65 Ft. Lbs. Mains Torque at 70 FT. Lbs.
Start in the middle and go in a circle
You can find them here->http://www.boxwrench.net/specs/chevy_sb.htm
all small Chevy heads are 65 ft lbsin a circular motion from the center out
i retorqued my Chevrolet heads to 90 ft. lbs. but i also found if you use the specific torque pattern the gaskets will seat better....i don't torque my intake boltsAnswer65 lb.ft.
call your Chevy parts man at the dealer and he will be able to look it up for you.