This is an adapter unit that puts a GM HEI control onto the Ford trigger unit. The Ford trigger units are so bulletproof it hard to find a dead one (that hasn't been phyically injured). The one in my bird got about 145,000 miles in a pickup before I became the "new" owner. The Ford style controller units don't like a low resistance coil or no ballast resistance - they overheat. 

This will work with a low resistance coil and no ballast resistor. It has a "smarter chip" than the Ford boxes and uses dwell time to control heating of the transistor. This is what it looks like built onto an aluminum heat sink plate the same size as the Duraspark II controller.

I refitted my outfit with an MSD low resistance "TFI" coil and a lower ballast resistance so the total was about 1.8 ohms. The Ford type controller (a Wells unit) didn't like this much and imediately started heating up at low rpm. It did make a significant visual and audio difference when viewing an open plug firing out on the manifold. Nice blue sparks and "cracking" right along.

This new unit was installed with "jumpers" for a test. The ballast resistance was then removed so it was firing a coil with only .9 OHMs internal resistance. It looks (and sounds) like a little arc welder - and the module doesn't heat up like the Ford units do. You must have a #12 or larger hot wire to the coil + - and it needs to come from a power relay not some old dash switch. This thing has a considerable thirst for AMPs and Volts. The idle actually improved a bit - I'm pretty sure it lights the fire no matter what.

New HEI module (standard 4 pin type) is dirt cheap - I got this "hot" one off ebay for less than $20 - the regular type HEI's are available at virtually every auto parts outlet. Spare fits in the ashtray and can be changed in minutes with no burned fingers. The Duraspark style system with divorced trigger and controller is far superior to the Pertronix in terms of troublehooting and repair (changing parts). The hot chips like the one shown here have a higher capacity for heat and an even smarter dwell computer - pushes the effective rpm up over 6000 revs (not for me).

This is old news to some - I've just been slow adapting it to my green machine. There are guys around who claim their hybrid set-ups have been running with this arrangement for years - I'm going to find out for myself.

                               Steve Metzger               Tucson, Arizona

These HEI controller conversions are all over the internet and I wanted to try one on for size. It appears to work just as advertised, and you can't beat the price. One atricle I read claimed that with the right four pin module (extended dwell set-up) it would out do any inductive system on the market - and from what I've seen so far they are correct. Only an MSD red CD box would be a better choice in my opinion (for pure spark power) but they don't get fixed this easy either.

I fitted the distributor with one of the "mustang" style HEI type caps to get a better high voltage isolation system - Ford thought it was a better idea so who am I to .....

disagree, right?

                               Steve Metzger               Tucson, Arizona

Alan Frakes ~ Tulsa, OK