Classic/Antique Car Repair: 1980 Trans AM, battery distributor, car jack

Question
Engine recently replaced but having problems firing up engine.  One day it works...one day it won't.  Replaced spark plugs, wires, battery.  Distributor Cap was rebuilt.  Any idea what could cause problem? Runs good once its started...could gasoline be problem?

Answer
Gas could be the prob.  Probably the timing advance system.  It must have electronic ignition.  I would look hard at that area.  I know Model A's, and not Trans AM's.  It's not the engine if it runs good when it does start.  It's not the plugs.  I assume they are clean and with the correct gap.  The dist cap sometimes can get contaminated with grease and oil.  We used to boil them in a mixture of tide and water.  Then wipe them dry.  If yours is new, that should not be the prob.  Try the old cap just for fun!!!
What about the ignition wires.  They can fool you.  If it was the gas, it would not continue to run good.  Check out the fuel pump for intermitant operation.  If it is an electric pump, it may be turning off due to something the system senses as being wrong.  Not sure what that car had.  Also, I would question the ignition switch.  When you are in the start mode, I hope things are "on".  It could be a function of how fast you let the key come back to the run position.  In the start mode, some things are turned off.
Sorry I can really help you.
Good luck with your car.
jack