Has anyone who has done a late TPI swap converted to a large cap distributor? I need a little help with getting the right wires to the right posiions in the weatherpack.

1. I have a spring latch early style large head distributor.
2. I have a late style TPI harness for the small cap distributor.
3. I have a early style female weatherpack connector to plug into the large cap distributor- once I figure out which wires connect to which wires.

Here are the colors and positions on the male large cap distributor pigtail-
A= Tan
B= Purple(ish)
C= Red(ish)
D= Black

Here are the colors and positons on the harness-
A= Black/Red
B= Tan/Black
C= Purple/White
D= White

Aside from the black (ground) where do the other three connect to each other?

 

Well, I solved the dilema after hours of combing through schematics and websites.

I was able to validate the pin-out changes on Holley's website where they show an adapter for a large cap harness (their Commander system) and a small cap distributor. I also validated the pin-out for the large cap connector on EFI Connection's website, through AutoZone's online schematics, as well as several of my own for late L98 F-bodys, L83, L81 Vettes.

The difference between 1981/82 Corvette distributors and F-body CFI distributors are minor, usually limited to wire colors.

All large cap distributors deliver the same data back to the ECM. The difference is in the pigtail and the cap. The alignment notches on plastic terminal shrouds for the very early computer controlled HEI distributors don't line up with the later style 85-89 connectors. Not a problem for me- I already have an early weatherpack. The next difference is the fact the early stye cap uses springs and latches instead of screws like the later model distributors. This is irrelevant to me.

Otherwise, this is a very straight-forward swap.

Essentially, the wires on a small cap distributor line up in a mirror image to the large cap. The wires have the ground in the opposite pin-outs and then everything else lines up in the same order as the pin-outs move away from the ground.

Here is the solution to swapping connectors:

The wires for a small cap to large cap look like this:
Small Cap leads__________________Large Cap leads
A= Black/Red-----------------------D= Black/Red
B= Tan/Black-----------------------C= Red
C= Purple/White--------------------B= Purple
D= White--------------------------A= Tan