if you find a st170 engine then thats the one to use, head is 1000% better than others and the rods and pistons are also a lot stronger or should i say the pistons are forged if you drop new lower comp pistons in it put it all back together with some nice arp bits right turbo and management you'll have a comfy 300 horses or 350 if you fancy it only problem is a gearbox that will take prolonged punishment with all the torque you'll have