There was an article in the November issue of MM&FF where they made 606hp(engine dyno) from a 370ci motor w/ T&L ported Victor Jr. heads fwiw. The heads supposedly flowed 321cfm on the intake side and 227cfm on the exhuast.
If I'm not mistaken Victor Jr.'s are good for 500hp right out the box. No porting necessary. Id say just get a bigger roller rocker either a 1.7 or 1.72 and you'll be at 500hp with at least 9.5:1 compression.