[Brad_bb]

Apparently there is a slight difference due to the size of two different intake valve diameters. Actually I know valves were purchased for the heads I have and something was funny as to the size, and this probably explains it.

Geeteeohguy, when originally looking for forged pistons for this engine(hate to say it but it was in the early 90's), the TRW's were the only ones found and they are flat top with 4 small reliefs. Who has these dished pistons available for the 389? Second, I am hoping I can modify these if need be and not have to mess with a new set. So they could either be machined flat or dished if I knew how many cc's I needed to remove. It's not much to remove go get in the ball park. In a rough calculation, I figured removing about .045 to .06 flat would get the cc's in the range of 89cc's total. I'm trying to figure out if 89cc's is the number to shoot for? If I knew the total cc's to shoot for I could get there. Then I'd just have to figure out the appropriate piston shape in removing the material. I'd also have to verify my deck height by mocking up the engine, and actually measure the cc's of the heads.
Lastly, you said the heads cc'd at 69, but what was the total cc's at TDC? This would include the dishing, the deck height, gasket volume, and head. And what cam did he run?