mongoose87

I know this has already been discussed quite a bit with new HEI distributors, but I can't figure out how EXACTLY to run the wire through the firewall.
I know I need to hook up the wire to the "IGN" spot on the fuse box in the cabin, but do just run the cable behind the fuse box into the engine bay, or do I have to disassemble the dash to get access to the ignition shielding hole?

Any pictures would be nice.

Dynra Rockets

I used the factory junction block. Purchased a new type 56 blade connector.

See post 14 here https://www.corvetteforum.com/forums...-location.html

TimAT

I'd run the wire from the engine bay TO the inside. Pretty much pick a grommet that has some room and stuff a 10ga wire thru. Lots easier to find it hanging under the dash than trying to reach up under the dash to find a hole.

TimAT

OR as Dynra Rockets did- but that does require splitting the bulkhead connector on the front side of the firewall. It does make a much cleaner install that looks factory.

mongoose87

Those pictures help out so much.
Thank you.
Although, which one is for the IGN position on the fuse block?



Which one is for IGN?

'75

You could check with an ohm meter. Just put one lead to the old wire from the coil and touch the connector contacts to see which one has continuity. Might be"F" or "G".

lionelhutz

You are replacing the coil wire that is already there. So, you have to unwrap the harness and trace the old wire to the block since it's coming out anyways. Or use a continuity meter to find the right terminal.

Dynra Rockets

Its been so long I have forgotten. I just followed the wire back from the coil to figure it out the first time.

mongoose87

so just a little update for the records.

I routed the new 10 ga. wire from the IGN port on the fuse panel, through the fuse block grommet and to the new HEI distributor. (The bubba way)
Man, what a difference.
This accomplished 2 problems for me, my tachometer works now, and the car getting power back.
When i pulled out the old distributor, the weights were gummed up and weren't flinging out to accelerate the timing. The initial timing advance was also set to 0 degrees. So the thing was running poorly and eating gas.
If you've seen my other threads I started about carb issues, and whatnot, this was the real problem.
I put in a CRT HEI distributor (cheapo) claimed to be made for 1968-1974 corvettes, and it works well for now. I haven't re-gapped the spark plugs for the additional gap yet, but I plan on doing that soon as a comparision to see if it really makes a difference.

I'll update if I see any issues after its run a bit more.

mongoose87

Another note:
Running the 10 ga wire to the fuse panel, then through the firewall is NOT a good way to do this. It's less professional looking, and if you accidentally put your foot up there while driving, you can knock the new wire loose, like I did. I accidentally shut off the engine while cruising down the road in traffic. Not super dangerous for me at the time, but it could have been.
I routed it to the fuse panel in the beginning because it was easy and I just wanted to see if the new HEI distributor would work. (I bought a cheapo dizzy, so I was a little worried)
I will change this out, as others have said, to run to the fuse block to the existing resistor wire location.
This is going to be a big pain because of the location of the fuse block on the firewall is below the brake master cylinder, and you can't really see very well from the bottom either.
I learned my lesson though, and will figure out a way to do it.