I used the Kieth Black 240's and had the block zero decked. They have a -8cc dome from the valve pockets and with a factory open chamber head give you about 9.5 to 1 compression. These pistons require a larger than normal top ring gap so read the instructions if you use them. They are also much lighter than stock pistons. I also went with the 440source h beam rods and had the bottom end ballanced. A forged 383 crank is a good idea. It is a bolt in swap and can be had cheap. Just remember they are internally ballanced and the 400 cranks are not.