When the problem first appears, unscrew the sight plug from the fuel bowl and check that it just barely runs out. Fuel bowling in the system or needle and seat problems will cause a large quantity of fuel to pour out. Careful of getting fuel on the hot motor. Also, open the gas tank and see if it is highly pressurized.
If no fuel pours out, watch the accelerator pump discharge nozzles in the carb when you work the linkage. You should get a good quantity of fuel squirted out.
The roadside procedure for checking a Mallory Unilite module is at
http://www.centuryperformance.com/mallory/unitest.asp
The procedure for MSD is at
http://www.msdignition.com/
While this may not do you any good, I suggest these procedures because I have experienced similar problems with my own cars and the problem has tended to be one of these.
Good luck.