As I said, the ONLY wire you need from the OLD system is the 12v feed FROM the Ign. SW. ..that's all.....the rest of orig wiring is not used.

The Pert goes Red to + of coil, Blk to Neg of coil and The 12v Ign wire couples up with the Pert Red on the coil +.
It is that simple.

I think your confusion of a ground wire is b/c some guys use a ground for the distributor b/c sometimes the dist does not have a good ground to the block due to dirt and crap at the lockdown bolt or dist plate...but the test I gave you verifies that. Another Simple test for that is to simply take a V reading using the plate in the dist for neg test lead of your meter and the pos of bat for the pos test lead..that V reading should be the exact same V. as your Battery V...if Yes, then you know the dist has a good ground as it sits and needs no further grounding .

Note**
This Dist Ground verification test does not require key ON...it is just a dist. ground test.
If the V is not the same as the battery V, [ less than], then you have a poorly grounded distributor. [ which will effect the Pert module/system , as it needs ground to power both the Pert and complete the coil circuit.]

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A Dalton