Hi Glenn,
first: my english is not the best...but my heart beats mopar

I have the same problem with the sec. My engine is a 383cui, with a weiand dual plane and first with a standard 600 Holley. All the basics are o.k. But the sec. will not open. (I have 2 Micro-switchs on the sec. to see on 2 LED's on the dash what's going on) If I open the primarys and blast a little air thruogh it the sec. opening very easy. (with the white spring) The same play with a 625 Road Demon and a 650 Speed Demon VE. If I drive a Kickdown from 3rd to first the sec. open 30% but not if I drive all gears manual until 5500rpm with throttle full open. What the hell is the problem ?? Have you find a solution until now ? Greetings from Germany Mario