An old TRW catalog shows the dome to be 10.4cc.

In my 0 decked 289 with Dart II Windsor Sr. heads milled to 60cc it comes out to about 11.3:1 compression. This was my impression when the engine was built years ago.

Now I have two conflicting reports.

Sources say that the deep valve pockets in front of the dome is 8.64cc, offseting the dome cc, leaving a total of 1.76cc.

This puts my compression at about 9.9:1.

Another source indicates that the valve pockets completely offset the dome volume giving no compression increase at all, allowing larger valves with no compression drop.

This puts my compression at about 9.7:1

So whats the final word on these pistons?
Could they really not increase the compression as we thought?

Does someone have one that they could check the dome cc against the valve pocket cc?

Paul

The difference between the cylinder calculation and the cylinder fill is your dome volume. Use the same equipment to measure your combustion chamber volume. Get the gasket volumn from the gasket maker and measure the distance between your piston at TDC and the block deck.

Using these accurate measurements is the only way to know what your compression is. Anything else is just a guess and could be a point or more off.