It would be a very good dyno shootout. Just need $30,000 and a year or so to round up the parts!

I'm pretty sure I know how things would stack up but there is typically a surprise in the pile. Big question would be the cam. You can stack the deck either way by optimizing the cam for one end or the other. Probably get the best reaction from the crowd by using a big cam that was designed for the -1 heads. Then you get a big bang at the end of the shootout.

540 with 13.5 compression and a ported intake with a 1250 carb should make 750+ with the 270 heads and end up around 850 with the -1 heads.