You must know a few facts first. 347's are not good for street driven stangs. The rod ratio is too big and will cause early ring wear (blow-by) and may even cause the cylinder bore to become elongated. Basically, there is too much side load on the piston and cyl wall since the piston travels too far down into the bore. Stick with a 331 if you want a 302 based block. Better yet, go with a 408. It will make way more power, and live a lot longer too. Yes you will have to buy diff headers, oil pan, motor mounts, etc. But you prob were going to buy new ones anyway, right. The cost difference is minimal. I suggest reading MM&FF March 2002 issue. Article is called "Stroker Ace" on page 104. It can explain much better than I can. Good luck. Make a wise decision so you only spend your $ once!
