A .015" shim style gasket will get you a bit more compression ratio. and is as durable as any.
The thickness of the head gasket has no real bearing on wether the head gasket will fail.
The heads either seal or thye don;t. Detonation and overheating will blow out any gasket.
A smaller chamber cylinder head really kickes up he compression ratio on that motor to good effect.
The cam in that motor needs compression to work.
You can degree that cam too and adjust its phasing ( advance it) for more engine torque too.
Adjust the cam timing so the intake valve closes @ 38deg BTDC @.050" insterad of 46deg BTDC.
You can shave those heads down to the intake valve seat edge to get compression but a 58 to 64cc head really gets it done ( especially with porting)
if you have not ported those heads then most of a 3 angle valve job gain will not be realized.
Get the cr up as close to 10:1 as possible and port the heads and move the cama bit and it will be a whole different motor.
That cam was designed for a 11:1cr and a 4 speed transmsision (1969 corvette 350-350hp L-46)
It is a dud with low compression. GM phased it 1deg retarded 115-113 centers 114 LSA
advance it for 107-121 centers and 38-39deg intake closing point (.050" lifter rise)
Degree the cam and you will see what I mean.
A ported 4416 heads with 1.94 valves installed with a shim gasket (felpro 1094) is a favorite low cost hop up on that motor.
More flow+ more compression ratio.
Don;t be shy with the porting on either of these stock heads. You got to lean on that die grinder to wake them up.
Then a nice 3 angle valve job pays off.
Last edited by F-BIRD'88; 01-30-2013 at 12:27 PM.