It all depends what power he wants to get Ive put a st170 bottom end in mine with the blacktop head on it for my turbo in my 2b I really wouldnt bother with the vvt. Chris (tractor) had nothing but problems with his vvt and now hes going turbo also. The engine mounts on the st170 are the same as the blacktop so if there the same as the silver top thats easy enough to do I just dont know if there is any difference in the exhaust outlets