Won't Shift Into Gear While Running

Been doing a lot of research on this issue and hoping maybe somebody can come up with something I've missed before I pull the trans.

So background, car is a 1969 Dodge Dart with a 340 4 speed. Car is all original, numbers engine and trans. Finally got it to the point where I'm ready to test drive it. Start it up and can't put it into any of the gears while it is running. I can get into all the gears when it is off however. Crawled underneath and it looks like all the clutch linkage is working correctly (again, using all factory parts here, think the only non-original piece was the car had the wrong Z-Bar so got a reman one from Passon). The clutch pedal is adjusted properly and the throw out hits the pressure plate and the clutch moves out. If you put it in first when the car is off and start it the car jumps forward.

Best guesses so far, maybe clutch in backwards? Another guy put the engine and trans together a year ago so I wasn't the one to put it in. Anyway to see if it is in backwards while in the car? Can't really see up there. He said he used a roller bearing pilot, could that have seized? Any other ideas? Think I'm going to have to pull the trans, ugh.