351????

[Unit 5302]

Probably what makes a bigger difference in longevity is the location of the pison pin in relation to the ring lands. Push the pin up into the oil control ring and you'll have some oil control problems here (and down the road combined with the higher rate of wear).

From my understanding, that is one of the main reason the 347 kits should not be supercharged, MiracleMax.

If you were looking at a block strength aspect, an A and R block 302 would be stronger, but the R block really can't be run on the street because of cooling problems, and the A blocks are pretty hard to come by since they are no longer made. Since the A block can actually be used in a street car and the R can't, it's added even more demand for the A4 blocks.