the factory rates this combo at 10:1 compression. i think it comes out to more like 9.6:1 in actual fact(it has been awhile since i ran the numbers through a compression ratio calculator, and it also depends on how far down the hole the pistons are).
Static compression is 10.6:1. This is considering .060 overbore and +0cc for flat tops. Dynamic compression will vary based on your cam specifics but it should be close to ~10.0:1.
what about head gasket compressed volume and head gasket thickness?
Cylinder Diameter (inches) 4.060
Stroke Length (inches) 3.00 (302)
Number of cylinders 8
Chamber in cc's 58cc head plus 6.78 cc compressed volume on the gasket
Piston flat tops so 0
Gasket Thickness in inches 0.32
most head gaskets for the small block ford are between .043 and .058 in thickness, and the piston is usually between .002 and .010 down the hole. that is why i say more like 9.6:1 is closer to accurate.
Most flat top pistons have valve reliefs of 4-6cc. If we assume 5cc, .040" compressed head gasket volume, .005" in the hole, and 54cc chambers, 4.060 bore, I get 10.1:1 static compression.
How are you getting 10.1 to 1 when your adding 6cc more and useing a thicker gasket than I did in the calculator and I only get 9.9 without adding 6ccs and a thinner gasket.
I'm not saying I don't trust it I'm just trying to figure things out. If I don't understand them then I don't know how to do it and it buggs me. I don't like asking questions I want to be able to figure it out by myself but some times you have to lol.
Depends also on the pin height of the pistons used. Most are either 1.585 or 1.605, a few are 1.610. The 1.585's will give around 9 to 1, the other two will get it to 10.0 to 10.5 to 1
Yeah, you have to know the C-H and deck height in order to estimate the piston-to-deck height, which plays a big role in CR. I ran across C-Hs of 1.165-1.175 for the 331. I guess the same must be true of stockers in order to accommodate different deck heights (from decking duing block machining). Good point.