I had a 347 kit on my 95 Gt and I had problems. It was put together by UPR in S. Florida, a very respected competing racing shop. It was a nightmare. Then Went with a custom 331 kit with dished pistons for my blower app. and wow...what a difference. If you're gonna use a 347 by it self with NOS, its an OK kit. But if you want to put on a supercharger, well go with a 331. I am at 590hp @ the fly and 509 @ the rear wheel. I drive it to work every day as well as take it to Moroso race way on Friday nights....Good luck on your quest....