Who has the fastest /6 here

You would better off trying to duplicate the head the dragmasters used.....furnace brazing tubes straight into the intake valve and eliminating the bend(and restriction) of the stock head. EFI makes this easy to run. Dad had a lot of heads flowed on the same bench and 210cfm at .500 was about the best number. One head flowed 230+ but the low numbers were worse than a stock head. The chart should still be on ss.org somewhere. Every head we ever flowed stalled/flattened above .550 except for the 230 mentioned above.

Waste of time making an aluminum head for a slant in my opinion. Money is better spent on a boosted set-up, stroking or extreme diet.
BUT its your $$$ spend it however makes you happy and have fun.