240/300 distributor swap question


Well-known member
I am finally making the swap to dual advance after recognizing the limitations of the loadomatic system. I already had a late 223 distributor and oil pump with the 5/16" shaft, so I went about removing the drive gear from my old distributor and my new 240/300 unit. What I have found is that the gear on the 240 distributor has a small protruding step, or collar, between the gear and the distributor body, whereas the 223 gear is flat. The result is that a direct swap results in far too much end play on the new combination. Additionally, both gears had to be pressed off the shafts after removing the pins, but I was able to push the 223 gear on the 240 shaft by hand.

Do I need to be finding shims/washers to get the end play right, or should I re-drill the roll pin hole in a new location? What, if anything, should be done about the fact that the 223 gear doesn't have to be pressed onto the 240 shaft?

I appreciate any advice from those who have done this swap!


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Staff member
Supporter 2021
Supporter 2019
When you start out it's important for you to carfully measure the 223 Distribitors drive gear position from the block mounting flange and also check the gear to distributor bodys end play by measuring with some feeler gauges. I. E. This distance from the base of block mounting flange to the gear location of the swap 240 / 300 distribtor with the 223 gear installed should closely duplicate the gear position of that on the old 223 Distribitor. Yes you may need to use some shims or washers to adjust the 223 distributor gear end play to the 240 / 300 distributors body. There shouldn't be excessive end play between the gear and the distributor body allowing the center shaft to walk upward any more than the original 223 did. If the drive gear fits the shaft closely (i.e. You can't wobble the gear on the shaft) then it's going to be fine it's not nessiary for the gear to be a press on fit. Good luck this will be a great upgrade for your 223.


Well-known member
When I did mine I took both distributors to a local machine shop and told them to keep the same distance as the old distributor. I had a extra gear for them so they could use my old unit for reference without taking it apart.


Well-known member
I was able to drill a new pair of holes in the gear collar and obtain the right clearance and gear-to-flange spacing. Thanks for the help!