I thought I had the 74 but I was wrong car ran good for a 2 days and I have no spark going to the coil or distributer. The battery is reading about 13.5 volts and I am getting fuel to the carb. We hooked up a test light to the coil on the positive side cranked the engine over and had power to the + side. We did the same to the negative side and the light lit up again. I only have four wires hooked to the coil + side has red wire from the distributer and the ingation wire. The negative side has the green tach wire and the ground for the distributer. The distributer is a complete petronix electronic system I cannot find any adjustment for the magnetic pickup in the distributer. We even tried just hooking up the ignition wire and it still gave power to both sides of the coil.
The petronics may have kaput. if you still have the points, put them back in. Tack wiring may have grounded somewhere an shorted out the petronics. Was anything redone after you had it running?
there were no points to begin with it was a brand new crate engine. No nothing was redone just put pipes on
put an hei dist. in it. 1 wire to power it, no coil, no box, . 65,000 volts and no headaches.just my .02. other than that sounds like the box took a dirt nap, or you have a short as was previously mentioned.
Here some more strange news I am not the only one with this problem, a friend a has a street rod with the same distributer I have and now he is losing spark, and I found out that another guy with a chevell is having the same problem no spark (beware electronic users) What kind of hei dist do you have?
If you got power to at both sides of the coil, the module is not switching the coil. It could be a bad ground to the module, a bad module, or a bad pick-up. You can ohm the pick-up (disconnect first) to see if its that. If the module is grounded to the dist housing, use jumper cables or something of the sort to connect the dist housing to the neg battery terminal. If you don't find it there, buy a new module.
its a dui style. and no, the wires aint just hangin there now, this is an old photo. but it cleans up the bay nicely,not needing anything else.