heads ??

[idontno]

What does "closed chamber heads" mean?
Oval port heads?
Is there a standard size intake/exhaust valve in a stock BBC head?

[durty]

closed chamber generally means small combustion chamber, and oval port is the runner shape

valve sizes vary, not all heads have the same size valves

[idontno]

Is a small combustion chamber better? Just to use some numbers, from what little I have seen, it seems that a 64cc chamber is generally perferred over a 72cc chamber. Is this what you mean by small chamber? What is the advantage of the chamber sizes?

When you say runner shape, what does that refer to?

Sorry if my questions seem to be on the dumb side, but I am just getting started on trying to learn about motors. I wil probably have dumber questions in the future. lol

[msims]

if you look on the side tht bolts against the block ,the hole where the valves are sunken into is combustion chamber ,,, open chambers flow better and burn up the fuel better ,,,be like a piece of pipe if it had something plugging it a little bit it wont flow asmuch as one tht is not stoppedup ,,,, the runners are the passages frm the intake through the head to the valves ,, same deal here in most cases bigger flow better just like a piece of pipe but shape also makes a difference ,,

[msims]

i guese i not answer your question complete ,,, air can be compressed , gas when not compressed only burns and not blowup , like when u pour gas on the ground and light it it only burns ,, but fast enough u think it blows ,,but under pressure it blowsup ,, so if u take say 50 cubic inches of space filled with fuel /air mix and compress it into 10 inches of space makes it blow harder thn if it was compressed into 15 inches of space ,, too much compression and it explodes b4 the plugs tell it too,,, small chambers make more compression but not let as much fuel/air mix in ,,,match head combustion chamber size wth the piston top shape to get the flow amount and compression u need ... if u hve a motor tht has dished pistons and open chamber heads //no compression ratio u can put heads wth smaller chambers on it to change ratio easier and cheaper thn new pistons

[idontno]

Thanks msims. Actually makes perfect sense. I don't know that I will know exactly how to match things up right away, but I understand your explanation. Thanks again for the help.

[zziggy]

Closed, Open chambers and Oval ports refer to Big Block Chevy heads.
CC (closed chambers) are about 106cc in volume from the factory, OC (open chambers) are about 16-122 cc in volume.
The OC heads unshroud the valves but also require a massive dome to get any compression in the engine.

Small Block Chevy's typically have 62-64cc heads from the 60's to 1970. Typical compression ratios were 10.25:1 to 11:1 on a 350 with flat tops (10:1) and 0.100" domes on 11:1 motors. 327's have domed pistons.
69-70 350 2bbl 9:1 engines had flat tops and 74 cc heads. 71-82 9:1 350's were the same.
Most 350's were 8:1 and had dished pistons with 75-76cc heads. All used steel shim head gaskets.

BBC had oval and rectangular ports. The Rect ports were on the top HP rated BBC 396, 427, 454.
There are peanut port BBC heads that go on HD Trucks, .5 ton and bigger and stationary power plants on 366, 427 and 454 motors.

Smaller chambers get more compression with less dome. Domes can shroud the valves at critical 0-0.200" lift flow.