Don the one thing you need to keep in mind is you need a custom piston period. There is not a shelf piston for a B1. However you can if they are still in good shape resue the current piston and go to a 4.25 stroke and new rod anbd have that solved. It does not have to be a break the bacnk thing. If those pistons are good that will save you some $$

IMO as suggested port the heads, freshen up the lower end throw a cam at it and let her eat. Otherwise open the wallet and do it once...BTW my little Valiant motor was a 511 with ported originals and it went 9.0's at 150 at 3470lbs with NO fancy parts at all.