I recently put a t56 into my 88 camaro. and when the car is off, i can shift through the gears fine. but when its running its almost impossible to shift it. it will go put you have to force it pretty hard. but if i start it while its in gear, i can move it. could the clutch not be engaging/disengaging right? what else could be wrong? could the slave cylinder need bled more?

 

Sounds like the clutch isn't disengagin completely. Whether that's because the clutch fork bolt isn't all the way screwed in, the fork isn't seated on the TO bearing, the hydraulics aren't bled all the way, who knows. I'd hedge my bets on air in the lines.