Blake,
Probe sells a 347 kit using a slightly shorter rod (5.315) which allows the piston pin to remain below the
oil ring. The eliminates the '
oil ring issue'. There may be others that offer similar solutions to the piston pin intruding into the
oil ring area. 331 kits seems to be priced about the same. In the end, sixteen cubic inches probably won't make alot of difference.
www.probeindustries.com