Speedmaster spark plug holes improvement??

How much compression?

The diamond pistons were 11.4-1 advertised but like I said the block was never cut and I did a fair amount of chamber work. I didn’t really want the open chamber heads but someone hurt one and I got them for 350 dollars. Easy chamber work fix and a couple valves. I ended up going with 2.08 valves anyway. On alcohol I fairly calculate final compression numbers. If anything I’m to low. Lol. This 408 I’m doing for 2021 CB68E2BE-A1AF-4F64-8D24-08378A8AF7D9.jpeg BFD55828-2EFC-4FBB-9759-85F5405D49D8.jpeg race season is a different story