Gavin unfortunately the valve inclination angle in the 326/ 389/421 heads do no lend themselves well to reworking them into a larger size like the one and only closed chamber 14 degree inclination angle head, that being the 670 casting.
If you go with a piston that has valve notches that total 8.5 CCs then you will have about a 9.75 compression with these numbers.
Head CCs 67
Head gasket CCs 9.4
Deck clearance .020”
Ring land volume. 1.5 CCs
Bore 4.100”
And those valve notches of 8.5 CCs., or a combination of valve notch and a small dish in the piston to get this amount of CCs.
At any rate the heads need to CC checked before any determination can be made .
Decking the block to get that right before boring and milling the heads as needed to get them straight can very fast make for a need of removing 4 CCs more from the pistons to stay on that 9.75 compression ball park.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!
1) 1940s 100% silver 4 cup tea server set.
Two dry rotted 14 x 10 Micky Thompson slicks.
1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.
Education is what your left with once you forget things!
|