Like I said, to get that much of a CC increase the chamber needs to be machined deeper.
This requires pulling out the valve seats to do that, then new ones need to be. Installed and a valve job done.
Since this work sinks the valves deeper then the push rod geometry needs to be gone over again and the spring pressures need to be reset.
Making the chamber deeper also shrouds the valves and reduces the air flow some what unless chamber work is done to counter act that.
I would just keep your heads as they are or maybe send them out to have CNC work done to unshroud them more to the tune of adding like 5 more CCs and then get your new pistons that have a 20 or so CC dish.
You absolutely do not want to run anything more then a .050” thick head gasket to keep detonation and knock at Bay!
A 10.5 compression will let you run the crappyest 89 with no issue and allow a good amount of street happy vacuum advance to be run.
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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!
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