tranny help

[jamal]

Me and my father-in-law placed a built 350 and a rebuilt turbo 350 in his 72. I'll have to post pics it is an awesome truck. The tranny shop is reliable, and I had a master overhaul kit with a shift kit installed. We thought the old tranny was bad b/c we couldn't get it to shift. When we put this one in it won't shift either. However, both will shift through all gears if I shift manually from 1st-2nd-3rd. All three gears work great and it shifts fast and hard like it is supposed to. He replaced mod valve, replaced rubber vacuum hose with copper, and nothing works. How much vacuum does this require? It is not a real strong vacuum due to being plugged in to a small nipple on the carb. The next step is putting the line on a bigger nipple to get more vacuum. Any ideas? I am racking my brain here. I don't know a whole lot about auto trannys.