72 GMC 1500 won't start after tune up

[revmbw]

Hey gang...newbie here. we just spent a couple of days working on my 1972 GMC 1500 Super Custom with a factory 350 engine. We replaced the plugs, wires, cap, points, rotor, manifold gaskets, transmission gasket and filter, fuel filter, air filter, pcv valve and of course an oil change. the truck was running before we did all this and now it will not start. I am very new to working on these trucks and am excited about what I will be able to do, but need a little help here and there. I would love some input. I think that it may be the ground wire, but am not sure...we did not mess with either of them, but they are both disconnected and am not sure where to reconnect them to.

Any help would be appreciated...thanks a million!!!!