SHELBY GT-40 ULTIMATE Member
Joined: Feb 2007
The problems you've probably heard about the 347 are from the early days, when the ring positioning on the pistons would allow it to consume oil. The newer kits have addressed this problem, so it's not near as bad as it used to be. Now, it'll come down to how well the engine is assembled and they can be maintained to live a long and powerful life.
Either the 331 or 347 will make more than enough power to satisfy your craving for power.
I would say contact a real engine builder, not a parts supplier.
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