Full Size Jeep Network

First time FSJ owner. 1983 Chief with 401 from a 1976 Chief. My husband gave me a FITech EFI system as a gift. Now trying to install. Can you lock out an HEI and let the FITech run everything? Or do I have to change to a non-HEI distributor? Cant find any wiring diagrams showing it wired to a locked out HEI. Any help appreciated.

to have Fitech control timing have to use a MSD distributor pro billet (I think), but the whole timing control thru the Fitech module is a pain in the arss, Fitech support really stinks but there is a independent Fitech forum out of Texas that pretty good I would join that.

It is typically dis-advised to use an HEI with EFI because it has a weak tach signal, so you can get weird misfires and such. We have had a few members here deal with it before going back to a motorcraft style distributor (Which the MSD is).

You CAN lock it out and let the FiTech run the timing, but, I wouldn't. I would run the HEI on manifold vacuum and let the FiTech do fuel only. That's what I have on mine and it works quite well. You might need to set a little extra base advance, I am on 14 compared to 10 factory.

https://fitechefituning.com/
here is the Fitech Forum link, lots of good information,I just installed Fitech's tripower set up in a 58 Chevy with a 348, MSD dizzy, in tank pump, the beauty and bane of fitech is it's versatility , if you don't want to deal with the details of fitech controlled timing then leave that sleeping dog,do really recommend an intank pump fuel pressure is critical so fuel pressure regulator/fuel return to tank
another good place for info is "vapor works" he really gets into the science of fuel pressure.
Cheers

I've been the FITECH timing control with a Jegs brand MSD dizzy for 2 years. It was not difficult to set up (there is plenty of guidance out there) and I have had no problems with it since install.