Re: crossram carb adjustments
Reason "Cross Rams" are not used with carburetors is that the benefit of stealth (a closed flat hood) is more than offset by the problems associated with an unbalanced plenum. You have to fabricate a balance tube connecting the two plenums together, or part throttle is going to suffer. That is why you are having these problems you are having now. Even at WOT a tunnel ram will still out perform a cross ram with runners the same size every time.
There is no one technique or trick aside from the balance tube (I have seen actual aluminum tubes of 1.5 to 2.0 inch diameter welded permanently in place (which detracts from the appearance and resale value in my opinion) as well as boring a hole and tapping it to accept a size twenty-four A/N stainless steel wrapped low pressure hose in each end of the plenum. Because of the dynamics occurring inside the manifold each engine build will probably be different (of course all 302 DZ engines using Concours parts will be similar in performance and tune). Increase displacement, change the cam or carbs, gearing even the initial timing will all have an effect upon the tune up.
You have to remember that these manifolds were used on race cars only. They were never installed on the car, and shipped in the trunk along with a set of headers from Hooker so that a Camaro could race on weekends, not drive down main street in morning stop and go traffic.
I strongly recommend the stock street driven set up the factory used in the Z of an 850 double pumper on a high rise intake. Actually I recommend a smaller carb and a better intake than the Winters manifold with it's square corners but most purist have a conniption if it isn't stock, ignoring fifty years of engineering improvements in the process.