[fleetsidelarry]

I think there may be other possible causes internally but if it downshifted ok with the q-jet logic says it must be the cable adjustment on the edelbrock.

is there slack in the tv cable at idle? there shouldn't be.

this where the pressure gauge test really helped me. there needs to be a preload of 2-3 psi above the unloaded (disconnected or slack cable) pressure at idle to ensure instant pressure rise.

but you don't want to pull it too tight at idle because you also need to make sure there's enough tv cable to match the travel of your throttle cable. of course you don't need the pressure gauge for that setting

(btw you said "I can definitely feel the OD working. It is a very small drop in rpms, surprising that's all it is. But it works.". I know it seems nit-picky, but that is the lock-up you feel, not "the OD". 4th gear is the OD. and yes, mine only drops at most 200 rpm)