Lou1119 Lou lets see what you don't have, Fuel or Spark.
Simple test if you have a carb, Remove air filter and hit the carb linkage ONLY once to see if you have fuel going into the motor.You should see a fuel squirt going down into the motor. If not, Pour a LITTLE fuel into the carb and crank it. See if it wants to start. If yes, we have a fuel problem. Look at what pressure we have. Does the car have ANY rubber hoses on it. It is very possible that the gas has eatin the rubber and clogged the filter or the carb.
Replace or clean out carb.
If fuel is not a problem. pinch off the fuel supply line. we need to check and crank the motor without having fuel being dumped and washing out the cylinders. Fuel line or fuel pump not running, next
Simple test, crank motor see if you have
oil pressure. If not you have either a stripped gear on the distributor or a broken pin for the gear to the shaft. Pull cap and see if you can rotate rotor with motor off. If yes broken pin. If you have
oil pressure this check the distributor and is working to a point. make sure the rotor is spinning. If spinning good. Check cap and rotor for burn marks or center contact being complete and not broken off. Put cap back on distributor. Loosen coil wire and crank, listen and check for spark. if you have it should be bright yellow. If it's barely there, we have either a poor sign or weak coil. What kind of coil do you have and where is it located. If you have an "E" coil the mounting does not matter. Just make sure you have good power and grounds to the coil and motor. Should have a min of 2 grounds. 3 is better. Either ground straps or aux cables of 10 gauge or larger. If you have an
oil filled coil, this is the orginial looking coils and it is mounted vertial on the motor, you could have burnt out the windings. Horizonal is better and off the motor is the best way to mount a coil. Spark weak, get another coil, You are going to repair a part at a time. Most guys that run MSD have double spare parts and the tools to repair on the side of the road. I have spare complete distributor, modules,(2) and coil. I burnt out caps a couple of times.
Back to repair, THIS IS VERY IMPORTANT, DON'T DO ANY TESTING WITH THE MSD SYSTEM ON. IT PRODUCTS ENOUGHT VOLTAGE TO KILL YOU OR GIVE YOU A HEART ATTACK. I HAVE BEEN ZAPPED 1 TIME. NEVER want to have that happen again. Tasted like battery acid for 3 days.
Follow the msd testing. If it's the module, send back to MSD. They will sometimes repair or replace for free. If you goto a swap meet. pick a spare up for about $100.00-$125.00. You can send it to them ahev have it checked. Same for distributor and coil. Put basic tools in a small bag to use if you need to replace them on the side of the road or call AAA.
That's about it. Make sure you are running the correct distributor gear on this motor. Bronze gear is no good. Steel, iron of polymer would be correct. Good luck Rick L.
PS I reread your story and I am thinking you have a loose ground or power wire in the car. Recheck the battery cables and connectors. Check the grounds to frame and motor. Check the ALT battery cable on the back for being tight. These thing will all cause the same problem. You said the problem happens when shifting, Motor and drive train move, think weak or loose connection. Check at starter battery terminal also. I don't know wear your power feeds come from and goto on your car. Verything tight and clean, no wiggling of wires on connectors. It might be something this simple. This would happen more when moving the car or hot driving.
Do this part first before going into fuel and Ignition.