I assume you are using an HEI distributor since you mentioned that you have a 4 pin module.
Are you running a full voltage (non-resistor) wire from an "Ignition ON" source to the BAT terminal of your HEI? This wire should also be 10-12 gauge.
What brand of module and coil are you currently using?
When you replaced the coil, did you also install/reinstall the grounding strap that is connected to one of the coil hold-down bolts?
Did you recheck your initial timing? Since you installed a new distributor... you may not have fully tightened the distributor hold-down clamp and the distributor may have rotated.
It may also help to know...
What your initial timing is set to?
How much mechanical advance are you getting and at what RPM is it "all in"?
How many degrees of vacuum advance are you getting and is your vacuum advance canister connected to a timed/ported vacuum source?... or a "full time" manifold vacuum source?