Ford 351W W/ 5.956 Rod, -12.2cc Dish Top 4.000 (FPS). These probe industries forged pistons will give you 10.55:1 CR with 58cc heads. Compression will be 9.51:1 with 64cc heads. Ring size is 5/64, 5/64, 3/16. These pistons use ring set 40564CP from Probe (also sold by Stage 3 Motorsports). Call 623-435-0166 with questions on this piston set. Price is for a set of 8 pistons w/o rings. If you need these pistons in .030 or .040 please list this info in the order notes section.