Back when I was playing with Chevs I dabbled with some aftermarket stuff and MSD, Mallory and Accel all got some of my money - too much actually. Once I got the advance curve right with these units they all went exactly as fast as the Delco, so wherever possible that's what I've stuck with ever since. Recently I decided to look into using them in the little six - the Bosch HEIs are very good, but they're getting old and worn and it's a pain in the arse changing the advance curve on them. As it turns out it's almost trivially easy to adapt a Delco HEI from an AMC Jeep 232-258ci six cylinder to the Holden engine. The rotation direction is the same, shaft size is the same, and the diameter of the body where it slips into the block is also the same. The only differences are the gear and a slightly longer distance from the tip of the body to the collar. Anyhow I thought I'd post the conversion details for anyone else wanting to make the swap:
1, Knock the roll pin out and remove the gear. Pull the shaft out from the top (after removing the cap)
2, Use a small socket or similar to tap the bottom bush up into the body about 3/8"
3, Trim the bottom of the dissy body to give about 1-1/8" from the bottom of the collar to the bottom of the body (if you hacksaw this by hand make sure you dress the base perfectly square and flat)
4, Blow any chips out of the body and slip the shaft back in, then refit the thrust washer and the Holden drive gear. Mark the shaft so you can cut off
5, Pull the shaft out again and trim it. Use soft jaws to hold it so as not to mark the shaft.
6, Oil the bushes then refit the shaft, washer and Holden gear. Drill a 3/16" hole through the shaft using the original Holden gear as a guide. Get someone to help you eyeball this to keep it all square if necessary. Obviously you'll want to use a metal gear for this operation even if you'll be using a nylon gear in actual use.
7, Tap in the roll pin and check that the end float is OK and shim if necessary. Fit the cap.
That's it, the whole operation takes less time than it takes to change springs in a Bosch. You now have a dissy with enough energy to run a six at 8000rpm+ and will now be able to make advance curve changes in minutes without even pulling the dissy. Spring and weight kits are readily available for a few dollars. The one in the photos is a repro HEI dissy with adjustable vac. advance and a two year warranty that cost me a whopping US$53 + freight, and it takes standard HEI replacement parts. The US racers in classes that must use stock ignitions swear by the Davis DUI dissies that are a bit more expensive at about US$300...
Converted Jeep HEI
Edited by oldjohnno, 25 June 2010 - 09:36 PM.