440Source has a 512 rotating kit or you can piece one together using cranks, rods and pistons from your vendor of choice. The problem is that for street driving on pump gas you need to stay around 10:1 compression and there are not a lot of piston choices that will give you 10:1 compression with the 78 cc Trick Flow heads. Diamond has a piston but that is about it and the Diamond pistons are expensive. ICON has a piston but the compression is a bit higher. You can always get a custom piston of course but that adds money to the build.