I have a 347 and love it. The pin is in the ring land area with no oil control problems. With good machine work, and assembally you would be fine. The rod to stroke ratio seems to be a big debate between the 331 and the 347 and wich one will last longer. I chose the 347 because of the extra cubes and it is a proven performer.
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79 hatch w/ NA 347,stage 2 Canfield heads, out of the box Victor 5.0 intake, solid roller cam, Aeromotive fuel system, proshifted TKO II.MY CAR
http://www.mustangworks.com/cgi-bin/...splay.cgi?1288
93lx all stock + tremec