For a 505 to make almost 700 with the Trick Flow (Howards) HR cam that is on the small side at 243/247 @.050 and ~.600 lift and only a little over 10:1 is pretty impressive.

In a way the smallish cam would help the upper bottom without really Killing much on the top end. It would be interesting to compare the same basic combo with a 240 small port with a slightly say +10-12 bigger cam @.050 to offset the smaller ports.

I know Andy motor did this to an extent but I think the cam was considerably larger.

From a pure streetability perspective it would be interesting to see what the SMALLEST cam duration you could run and still make say 700 hp with the 2 different head combos.

But with your combo if the intake is ported you should still make about 620 I would think. the .450-.500 flow numbers for the 270's should put you there even with a fairly low lift cam...the intake is going to be your limiting factor if the runners cant keep up with the Heads.

The issue with port matching a 906 to a MW isn't really the gasket match, it's making sure the mouth of the plenum to each runner can outflow the head flange enough to feed the head at the torque peak. I used to spend hours working on Street Dominators back before we had much in the way of MW manifolds. Anybody else remember those days?