Getting a smallblock to rev
There is no, excuse me, NO difference in 2 or 4 bbl heads because there was NEVER such a thing. The closest it did come to this was later year (mid/late 70's) 318's that used 360 heads for the 4 bbl option.
Port matching is OK'd by his rules as well as porting.
Balancing a engine is 101 type of work on any engine.