My car has the newer HEI in it (external coil) and I want to convert it to the older style HEI (coil in cap). I have an engine harness from an 86 TPI motor that used the older HEI distributor. My question is can someone show or tell me exactly how to make this conversion?

 

Splice the power and tach connectors from the '86 harness into your external coil power and tach wires.

What car are we talking about? An '85 should have come with a coil-in-cap HEI.

 

Thanks. The car is my 85 Iroc with a motor from an 86 Iroc and an engine harness from an 88 Iroc. Does anybody have pictures of how this is done?

 

So I take it I have to splice the 4 pink/yellow wires that go to the coil on the 88 harness into the 4 wire connector (to the distirbutor)from the 86 harness?
Then what do I do for the tach wires(which wires are for the tach on the 88 harness)?

 

As I understand it (don't have an '87-up thirdgen), the pink wire going to the coil is power and goes to the "BATT" terminal on the HEI cap. The white wire going to the coil goest to the "TACH" terminal on the HEI cap. The multi-wire connector to the inside of those connectors connects to the harness that comes from the HEI distributor base itself.

 

How do I know which pink wire goes to the battery since there are two of them? And I dont have any white wires, but I have two yellow ones that go to the coil.

 

any ideas?

 

Back up, chief. You need to look at the coil connection wires coming out of the WIRING HARNESS, not the wires that go between the coil and the distributor. The wires from the harness will be on one molded connector, the wires between the coil and distributor will be on a second molded connector, both connectors would plug into the top of the remote ignition coil (which, obviously, you don't have with a large cap HEI)

On the wires coming out of the engine wiring harness to the coil there will be a fat pink wire (that goes to the BATT connection on the large cap HEI) and a smaller white wire (that goes to the TACH connection on the large cap HEI).

 

Ok I found the pink and white wires, but now what do I do for the 4 prong connector that comes from the distributor?

 

plug it into the cap

when I read hold on chief I chuckled, thanks

 

How old an hei are you talking aobut? Mine has no 4 prong harness although I know what you're talking about from my 88 caprice. When I did mine I just ran the hot lead from the old coil to BAT and the Tach wire to TACH. I run a pre 80 big cap hei with vacuum and mechanical advance.

 

The HEI is from an 86 camaro and it has Hypertech Coil, cap etc.

 

Im sorry to say I don't know the unit. Like I said I had the small cap one, but my big cap hei's are all mechanical/vacuum advance. The instructions posted above sosund right though. Are you sure it'll fit with the larger cap. I had that issue with the 88 caprice.

 

So you want to plug the computer control connection from an 88 wiring harness into an 86 computer controlled distributor's computer connection pigtail? Now you may have some problems that aren't easily solved. I'd have no idea how to re-pin that connection to plug those 2 together. I don't know if it's even as simple a job as just repinning. I'd have questions as to whether they're even compatible in that way.

I missed that the first time I read through and responded. When most people are putting in a large cap HEI they're going to a non-computer controlled distributor and converting from EFI to carb.

 

Alright, if its not possible then Ill just leave the newer one in there for now.