Thanks Mark.
I read the posts on your site through "tap a talk" ( may not have written that correctly ) and, as you said here and i read in threads there- manifold design was a big deal and, we saw the results Andy got with the Wilson manifold work.

So, this car being bound to a 4150 flange and, needing more cfm , i called Wilson and we sent them a main body, the heads and manifold.
Results: we gained over 30 hp and the tuning window improved a great deal, manifold vacuum was more consistent through the run as well ( still not sure why on that unless its that reversion pulses are better?
Your thoughts on that would be helpful.
Afr graphs were much, much smoother and, fwiw, our left to right bank jetting stagger is only one jet size different now where it was 2 jet sizes before ( we use the Comp Jets ).
Passenger side bank still has the most fluctuation during the run, but, its not bad at all and way better than before we sent everything to Wilson.
Wilson was really helpful and understood what i was trying to accomplish .
As they hadn't ever flowed anything with a twin blade base plate and center section, I had one sent and they were able to fab the right carb spacer for heads/manifold/carb combo.
Its worked really well for us, i can keep the tune really tight and stay on the number until we get into the really bad sections of Texas summer air quality, might test some oxygenated fuel to help offset Texas air density this year.

The Twin has worked well for us with our specific needs in index racing .
We run throttle blades locked one to one, Iin texas heat/humidity i keep her pretty tight on the lean side ( best et/mph for us) and when its cool and dry, i can add some fuel .
My job on this car is to keep the car on the numbers all weekend so the driver can just focus on driving.

Thanks for the links!

P.S.

Is that an early Bo Laws center section or did someone else play with that design before Bo other than the holley 3 barrel?
Fascinating man!

Reminds me of looking at old Mark Levinson pre amps- grin.