Hello guys,
I am building a 427 motor and am working out my static / dynamic compression ratio. I have read that most chevy heads cc more than the advertised volume, my heads are 3904390 '67 427 Corvette heads, the chevy spec. cc is 98.4cc,
I have measured mine twice to be sure, and both times came out the same at exactly 112cc.
Thats 13.6cc over the factory spec, is this normal for these heads, or have mine been modded ?Anyone familar with these 3904390's.
I have heard of the mod. to de-shroud the exhaust valve on these heads, is it possible my heads have had this mod done, thus the increase in chamber, anyone have any photos of what a stock versus de-shrouded chamber looks like ?
Any info really appreciated !
I am building a 427 motor and am working out my static / dynamic compression ratio. I have read that most chevy heads cc more than the advertised volume, my heads are 3904390 '67 427 Corvette heads, the chevy spec. cc is 98.4cc,
I have measured mine twice to be sure, and both times came out the same at exactly 112cc.
Thats 13.6cc over the factory spec, is this normal for these heads, or have mine been modded ?Anyone familar with these 3904390's.
I have heard of the mod. to de-shroud the exhaust valve on these heads, is it possible my heads have had this mod done, thus the increase in chamber, anyone have any photos of what a stock versus de-shrouded chamber looks like ?
Any info really appreciated !