when you remove the distributor, it does not have to be at top dead center. any time i remove mine, i just mark where the rotor was before i remove it. when it comes time to put it back in, as long as the rotor lines up in the same place as when it was removed, it is fine. as i said before, 10* timing is 10* timing. the distributor being off a tooth will cause no problems if he got 10* with a timing light. as stupid as it sounds, go over the plug wires and make sure they are connected in the right order. if that is correct, i would begin the process of elimination with a tune up (plugs, wires, cap, rotor, fuel filter, etc.) also, you are going to want to check for any vacuum leaks. doing those things should solve your problem.