To calculate true compression ratio, it’s necessary to measure the distance between the deck surface of the block and the piston deck. Our machined aluminum deck checker incorporates magnets to hold itself firmly to the block for simple and accurate measurements. Mount a dial indicator (not included) in the center for deck height, or mount one indicator in each end to check piston rock. PartNumber : cca4900 Description : Magnetic Deck Checker Title : 4900 Magnetic Deck Checker California Proposition 65 : WARNING: Cancer and Reproductive Harm P65Warnings.ca.gov Uncategorized::Uncategorized