Weak and intermittent spark

Lost spark after taking a short test drive just after rebuilding the carburetor. Decided to renew the entire ignition system (new plugs, new plug wires, new rotor, new cap, new distributor, new coil and new ignition control). While I was at it, I also replaced the timing chain and water pump. I tripled checked the timing when installing the new timing gear. I know that is correct.

I get a strong and consistent spark from the coil (testing coil lead against block when cranking). I get a very weak and intermittent spark at the spark plugs (holding the plug against the block when cranking). I occasionally get a strong blue spark at the spark plug at the end of a cranking cycle (last spark after disengaging the starter).

I have 12.4 volts at the coil positive terminal and about 10.2 volts at the negative terminal when cranking, I've installed a jumper from the "I" terminal on the solenoid to the positive coil terminal to minimize voltage drop through the ignition switch circuit.

I've got 12 volts into and out of the ignition control module. I've installed two different and new ignition control modules. Unfortunately, I have not been able to test the ignition control modules as all of the local auto parts stores have either removed they test machines or don't have the correct jumpers to connect the module to the tester. Apparently a lost art at the parts store. In any case, since I'm getting spark (just weak and intermittent), and it remains the same with either of the new modules installed, I'm guessing that it is okay?

I've got the Prestolite distributor setup and I suspect that it may not be working right. As I said, it is a new (re-manufactured) from the parts store. Is there any way to test the Prestolite distributor using a voltmeter or test light? As I said, the spark coming from the coil to the distributor is strong. It just gets lost somewhere in the dizzy.

Any other ideas welcome too. I'm really searching for a solution.