Have replaced coil and modular also distributor cap
Still won't turn over.Checked for spark at plug and coil.You can only see a little spark, no real arching.It is a straight 6-4.9,4speed.Any ideas?

 

If you are getting a weak spark right off the coil wire to the cap, there are a few possibilities.
System voltage too low , battery weak
Poor connections in either the power suppl to the coil or poor ground in the system
Starter pulling the available power to the ign system down
Questionable replacement parts
Wiring with broken wire and only one or two strands holding together
Possible partial short (pinched wire) causing reduced power or ground to coil
Poor signal from pick-up coil in dist.
Also , remove plug from computer assy and check for any corrosion on any if the pins and plug.