[steve25]

It’s all guess work until one takes the time to CC each chamber on a head that has a valve job done to it and or has also had new valves installed.

Just a valve job could add between 1 to close to 3 CCs to the chamber volume depending on how much the valves where sunk, then on top of that dish face valves might have been used which could add another 1.5 CCs to a chamber with the large 2.11” / 1.77” valves.

[TRADERMIKE 2012]

Originally Posted by steve25

It’s all guess work until one takes the time to CC each chamber on a head that has a valve job done to it and or has also had new valves installed.

Just a valve job could add between 1 to close to 3 CCs to the chamber volume depending on how much the valves where sunk, then on top of that dish face valves might have been used which could add another 1.5 CCs to a chamber with the large 2.11” / 1.77” valves.

Give me your best estimate, I won't hold you to it. In my possession is one cracked Exhaust Valve that was removed and it is flat, two Exhaust seats were replaced as well and the remaining Valves are stock flat ones as well. I use the large Valves on my 1967 428 ci HO 670 D-port closed chamber Heads. A picture of my Pistons and Valves are in this post for you to look at, if you need to. Would it be out of line if I thought that I could be any higher than 10.75:1 CR?