Installing a Pertronix Ignitor III
Pertronix ignitor conversions have been a great option for Hot Rodders for quite a while now. These units offer the performance of a modern electronic ignition yet allow you to retain the stock appearance of the OEM distributor. Another great advantage is the relative low cost of the conversion. If you have an existing distributor, or an engine that is hard to find parts for this can really simplify your conversion from breaker points!
I had been running an HEI unit but it really didn’t fit well with the amount of firewall clearance that I had to work with, so I wanted to use a small body distributor. The first thing that I did when I made the decision to install one of these in my 55 Chevy was to find a good used distributor that I could modify. I actually happened to find a rebuilt points type distributor at an auto parts store so I knew that the bushings were nice and tight in the body. There are a couple different versions of the Pertronix kit available for this small block Chevy engine and I chose the Ignitor III version because it offered the built in rev limiter.
The first step is to remove all of the OEM points equipment. This is as simple as taking the rotor off, removing two screws in the points plate and take the points/condenser off and discarding them. My kit contained an adapter plate that bolts down to the distributor and the actual ignitor module bolts up to that.
Run the wires outside the distributor body, replace the rotor and you are good to install the distributor. I also chose to install MSD part number 84333 distributor cap on my OEM points distributor body (yes it does fit perfect!) so that I could retain the same HEI type spark plug wires that I had been using already. MSD part number 8222 (with the sticker removed for stock appearance) was the finishing touch for my Pertronix conversion!
For final adjustment I chose to set my timing at 12 degrees at idle and 36 degrees total, mixing and matching advance weights until I got it right where I wanted it. This engine happened to have a pair of 461 camel hump heads and so with the slow burning combustion chambers I can get away with a little bit more timing than some more improved heads would allow for. This ended up being one of the quickest yet most dramatic improvements I’ve made to the car so far!