The biggest gains (besides obviously increasing the port cross section) one can do to a CONVENTIONAL) dual plane manifold, is to do all you can do to minimize the acute angles in the plenums. On the lower plenum (since you can't see it) I would just grind through them and build them back up with a smoother turn as well as really work the turns from each plenum Half to it's 2 port runners. If you wanted to get really tricky you could drill out and tap for strategically placed npt cast iron pipe plugs for better access to the ports and then grind them smooth and epoxy over them to duplicate to OEM finish once the porting is done.

But I still think testing and tuning against something already good (like a Performer RPM or a 440-2D) to baseline your combo is probably the best way to see how good (or bad) your porting is working and reflect the Potential HP the combo can make.

It is really time consuming and I really 110% respect the devotion these guys have in pursuit of these amazing ET's.


I forgot about the Max Wedges, yeah I would think they might go deep in the 9's with enough cubes and compression, the 60's ports are archaic by today's standards but they didn't run roller cams, gas ported pistons and 2.25" intake valves back then either! Can they run an aftermarket block like the hemis? 4.500 bores?

I still 100% believe FAST combos should be limited to a maximum of .060 over whatever the standard bore size was for the motor the car came with....I guess that cat is long out of the bag by now though.