Careful on the selection of 347 pistons , - sometimes depending on rod selection , the
oil ring will intersect with the piston pin hole, and the motor will consume more
oil than really needed. my personal preference is for a 326-331. Stock 4.00" bore to 4.030" and a 3.2" stroke. -- plenty of juice.
if you are more of a juice monkey, then you probably should be in a 351W Block -where you can go 402-408 with no big problems.
Steve.