To test for fire, just test for fire. Point the dist to #1, put on the cap, put a wire on #1, put a plug in the wire, and lay the plug on the block. Now put voltage to the HEI, and rock the distributor back and forth quickly. You should get a spark. Same thing to test on the bench... ground the dist. base, ground the spark plug to dist. base, put fire to the POS terminal, and spin.. you should get a firestorm on the plug gap.

In fact, if you plan to run the engine at, say, 20 degrees advance, then go one step further and rotate the crank until the timing markspint to 20 degrees ( advance ). Rotate the distributor back and forth, ( with afore mentioned setup ) and guesstimate the exact point where the spark is occuring. Snug down the distributor and you'll now be within a couple degrees of your 20 degree timing. Makes initial start up much easier.