When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
b16 pistons are labeled PR3 or P30 and yes they will fit in b18 blocks. all b16,b17,b18 pistons are the same diameter (81mm) the difference is in the height.