which are they i heard vette alum heads were 58cc and camaro cast heads were 64cc is this true i looking at new heads but need to know what ive got thanks

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1992 camaro RS
373 10 bolt rearend
ssm sfc's
87 350 TPI
bored 30 over
compucam 2032 with 1.6
482-495 LIFT 214-220 duration full roller rockers
msd6AL
1 5/8 headman headers
2 `1/2 flowmaster exuast
k&n filters gutter air box gutted maf
3 pc under drive pulleys
no emissions no egr etc
custom ED Wright chip
eddelbroc intake base and runners ported plenum
midly ported and polished stock heads
Taylor 8mm wires
B&M mega shifter
gutted maf/airbox
hotchkis lower control arms
3" exhuast cutout
homemade cold air intake
2000 tci stall
700R4 with B&M shift kit
new best ET 13.5 @104.66

and if they are 58cc how much compression ratio will i lose going to 64cc

------------------
1992 camaro RS
373 10 bolt rearend
ssm sfc's
87 350 TPI
bored 30 over
compucam 2032 with 1.6
482-495 LIFT 214-220 duration full roller rockers
msd6AL
1 5/8 headman headers
2 `1/2 flowmaster exuast
k&n filters gutter air box gutted maf
3 pc under drive pulleys
no emissions no egr etc
custom ED Wright chip
eddelbroc intake base and runners ported plenum
midly ported and polished stock heads
Taylor 8mm wires
B&M mega shifter
gutted maf/airbox
hotchkis lower control arms
3" exhuast cutout
homemade cold air intake
2000 tci stall
700R4 with B&M shift kit
new best ET 13.5 @104.66