intermittent spark

it is a 92 snob with regular 351 mallory blue top ignition and i am currently running a resistor with the coil , batteries are good

Schultz,
Besides what JP has asked, what testing have you done before replacing all those parts? You didn't mention points?

Might be good to have a little more detail-- i.e. cranks and does not start (assume so), Just requires basic troubleshooting when no start presents itself. Pull wire-- check for spark. No spark, go to primary (coil, resistor, primary wire)-- Experts here know the Mallory better than I do. I had an old Supra with 4160 carb and Pertronix ignition-- nuther can of worms. altogether.

When you replace a lot of parts all at once, it can unknowingly solve the problem or add new ones. Best to fix what is broke, then upgrade one item at a time (it makes troubleshooting easier). Hope you are good to go. If not-- take it one step at a time and work your way logically. I see a lot of folks get frustrated here when they change parts unnecessarily. BTW-- your "mechanic" ought to make short work of this stuff-- if not, find another mechanic.

schultz wrote: is there an ignition module in the distributor that could be failing? it is an electronic ignition. mallory

This is why I asked about points!!! It's an EI conversion and they are known problems. Go back to a point set.
BTW, I'd find another mechanic. It doesn't sound like he did very much testing to diagnose the problem and just had you throw a bunch of parts at it.