I may be switching back to the stock Motorcraft Distributor on my '78 F250 and would like to know what the best way to swap the distributor gear would be? When I bought the truck it had an aftermarket Accel distributor that has been trouble since I bought the truck and since the truck has an unknown aftermarket camshaft, I cannot just stab an old stock distributor in there without swapping the gear from the Accel unit.
Once I punch out the roll pin, should I freeze the distributor overnight or try heating the gear to get it off with my bearing splitter? Is it better to remove the gear from the shaft or is it easier to remove the whole shaft altogether and swap the whole thing in the stock distributor housing?
I hope to hear from those who have actually done distributor gear swaps before and not someone like myself who only has a theory on how it should be done.

 

There is nothing wrong with installing a new distributor with the gear it has. But if you are dead set on changing the gear it has to come off the bottom before the shaft can be removed. A gear puller will accomplish this but you will need the right jaw type to pull against the base of the gear(not the teeth) as those will break off rather easily on a cast gear.

 

Agreed, no need to change the gear. Install a new dizzy and call it good. HEI units are nice, but I prefer stock with a pertronix kit.

 

Unless the cam is a roller lifter model. Then there are different gear options. I've had trouble with MSD dizzies getting the gear on and off. Had to use a puller to get it off and heat the gear/freeze the shaft to get it back on using a socket for a driver and supporting the other end of the shaft on a cushion.

 

There is something wrong with using the gear on the Motorcraft distributor; it doesn't fit. As I stated, the truck has an aftermarket camshaft in it with an Accel distributor that matches the cam gear on the shaft. The new cam does not accept the standard size gear that's on the stock Motorcraft distributor.
A gear puller will not safely accomplish the removal of the distributor gear, that is why I mentioned using a bearing remover/splitter instead as to not damage the teeth like a jaw type puller would most likely do.

 

Why on earth would a cam manufacturer use a different gear pitch? What kind of cam is it? Maybe you need to swap cams and get a regular one. Whatever size/duration you want.

 

Heck if I know, I don't manufacture cams and distributors. As I said in my original post, "the truck has an unknown aftermarket camshaft." The gear pitch is not different between the stock distributor and the Accel, the difference is in the overall diameter of the gear itself. The Accel distributor gear is 3/16 of an inch wider than the stock gear.
The truck ran really nice and was quite powerful before the distributor started giving me headaches. The engine alone was dynoed at over 350HP and buying a new camshaft and matching distributor would not only cost more than I have in the whole truck(it's a long story), but it really wouldn't make sense to mess with a good thing. A distributor gear swap would also be a lot less work than installing a new camshaft.

 

What engine is it anyways???

 

OK.. you'll have to forgive us our presumptions because I can't say I have ever seen a combo like that, any cam you buys these days will have a standard diameter gear on it.

 

That's what I said! No reputable cam company is gonna make an odd ball POS. Unless it is for a very special application....

What engine do you have???

At this point, I'm gonna say you need to pull the cam, measure it and the gear and figure out what it really is. And possibly replace it with a cam better suited to your wants and needs. One with a STANDARD gear.

 

There are two common shaft diameters. .500 and .510 or something like that. Don't know why. As far as the gear teeth, the same dizzy and gear fits
351c, 351m, 400, 429, 460. The same dizzy works on the 351w with a "different" gear!