Need help to get truck started

[Lobo'74]

Actually, entire engine was rebuilt about 3 years ago. I bought it from an engineer in his late 40's who has been rebuilding engines and building hot rods since his high school days. LONG list of mods, but basically, sportsman II heads, flat top high silicon content pistons, cam, edelbrock performer rpm manifold, edelbrock #1407 750cfm carb, headers. The HEI was a new one when I bought the truck two years ago.

Just finished trouble shooting the system with the following results:
Test......................as measured................optimum...................results
Volts @ battery.........12.75 VDC ..................12-14 ?....................good
volts @ distrib. pwr in....12.5 VDC..................>12.......................good
Ignition Coil-
-----Primary Resistance...0 ohms ..................0 ohms.....................good
-----Carbon button-GRD...14.9 ohms.........not infinite resist.............good
-----Carbon button-BAT.....inf. ohms.........no measured ohms...........good
Pick-Up coil---
-----White - GRD........infinite ohms.............infinite ohms...............good
-----Green - GRD........infinite ohms.............infinite ohms..............good
-----Green - White......750-800 ohms...........500 - 1500 ohms..........good
Ignition Module..........pass on tester...........pass on tester..............good

Everything tested out to spec. The only thing I found that was not good was the wiring harness at the distributor. The one that goes from the internal capacitor then to the ignition module on one end, and to the coil assy “C- GRD B+” terminals on the cap on the other end. The harness was cracked all the way through the insulation on all three wires at both ends. Can’t get a new one at the parts store, they say its a dealer item.

I will get that on Monday after Easter and install it. Hope that fixes it. Other than the cracked dizzy harness everything else checks to specs. . .

Its a puzzlement.

[beaterC10]

A good parts store should have the dizzy harness, somebody like NAPA or Car Quest.

You might look at the coil, I had the same issues you are having. When I replaced the coil and the module with decent parts the issue went away. I noticed a lot of the cheaper ignition parts are made overseas and don't last long. I would assume that the Delco parts are good.