HEI Module

Well my Duraspark box crapped out. The van had a miss at idle that seemed to be getting worse, then the other day it crapped out and I barely made it home. It would die at idle and was missing badly at any rev. It deteriorated over the course of a couple miles. Lasted about 2000 miles

So I decided to take the opportunity to upgrade to an HEI module and a TFI coil. It was an easy rewire from the Duraspark II setup and only cost me $50 for the parts + $25 for a new wire set just in case. I'm happy to say it's running well, as good or better than ever and the miss is gone

I know others have done this, I just wanted to chime in and say I think it was worth it. But we'll see how long the Delphi module lasts. I mounted it to the interior of the empty shell of the DSII module with heatsink paste. It's under the driver's seat and I've felt it after running and it definitely get's warm as does the TFI coil.

I'd be interested to see how it performs. Do you have a link to a helpful guide to the conversion?

I basically used the schematic in these threads:

http://classicbroncos.com/forums/showthread.php?t=237108

http://www.hotrodders.com/forum/duraspark-module-overheated-engine-died-225477.html

I compared it to the DSII schematic and used the plugs off the old DSII module to wire the HEI in. One thing I did differently than shown in that schematic is I kept the black ground wire from the distributor and tied it to the HEI grounding which is also grounded via the mounting.

If you are still using the resistor wire that should be eliminated, both the GM ecore coil and the Ford TFI use full 12v. I have a relay that sends a fused 12v wire directly from the battery, relay is switched by the key. You also have to salvage or make a bracket to mount the coil on the engine, can be had from efi 300 f150's at the yards. Other than possibly some wire, fuse and relay, you just need a good HEI 4 pin module, some kind of heatsink to mount it to, either a TFI or GM ecore coil, and the connector for that coil. The module is around $20, the coil is about $25, and the connector pigtail is $5 all new parts. The coil to distributor wire comes with all the plug wire sets I've bought, it's that extra one you don't need/use.

Obviously, this only works if you already have a DSII distributor

Btw, I've read that the TFI coil has higher primary resistance than the GM's .45-.7 ohm coil. But I found that the TFI coil I used measured .5 ohms on the primary, so it's basically the same as the GM. It was Standard Motor Products #FD478, the connector was #HP4370. I used a Delphi DS10071 module.