302 Distributor Differences

51504bat

51504bat

Well-known member
Putting in a 302/AOD combo in my '54 Ranch Wagon. The donor engine had a carb and a mechanical AOD but it had an electronic distributor. I want to replace it with a stock type point distributor. My problem is that the electronic distributor from the 302 has an about 1/2" longer shaft than the point type replacement that I have. The replacement distributor does engage the oil pump drive shaft but only by about 5/8" or so. This to me doesn't seem like enough engagement. Anyone have any suggestions for a stock type point distributor that has the longer shaft like the electronic one I want to replace? Thanks.
 

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The replacement isn't a Ford factory unit. I do have a FoMoCo distributor that has the exact same dimensions as the aftermarket one I was thinking of using. The FoMoCo distributor has a dual vacuum canister on it that I believe is for both advance and retard functions. Not sure if I could swap the dual unit for a single unit or not. Regardless using it won't solve the issue of the shaft being 1/2" shorter the the electronic one. As far as he numbers go the electronic Motorcraft has Motorcaft cast into the body but no other numbers. There is an intermediate plastic cap held on by 2 clips under the distributor cap itself. It has a sticker on it with the number F2AF 12127-GA. The dual vacuum FoMoCo unit has C5AF 12127 N cast into the body and the numbers 5BC under the C5AF number. Thanks again for any light anyone can shed on this.
 
There were never "long shaft" points distributors made the long shafts are used when converting from EFI to Carb and using an aftermarket intake this is one style which is plug and play https://www.ebay.com/itm/373540338729?hash=item56f8bd3c29:g:HFMAAOSw0fhXl5IJ I have had one in my '54 with a 5.0 for over six years. All you do is run a 10 gauge wire to supply the 12 volts from the "I " teminal on the solenoid to the distributor,these use the same internal components as the Chevy V8 HEI's
 

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:rolleyes:

Another MING DYNASTY CHINESIUM GM HEI off-take.​

Before you pull out your CHINESE EXPRESS CARD, let me do some checking.
 
Not jumping into anything right away. Got a ton of other issues to keep me busy. Also, I got this info over on the HAMB. Kind of makes sense and since Ford did so many changes over the years dang near anything is possible.


"The later distributors have a longer shaft to make it easier to engage the oil pump while stabbing the distributor. Lot easier if you are already "on" the pump when you are trying to engage the cam and "Phase" the distributor. Saved trouble on the assembly line. Oil pump drive shafts are the same length for both."
 
The possible replacement isn't factory. But I do have the FoMoCo dual vacuum unit. If I can replace the dual canister with a single unit I'd like to run that one. So any further info on converting the dual unit or another option is appreciated.
 
51504bat said:
I do have a FoMoCo distributor that has the exact same dimensions as the aftermarket one I was thinking of using.

The FoMoCo distributor has a dual vacuum canister on it that I believe is for both advance and retard functions.
Not sure if I could swap the dual unit for a single unit or not. The dual vacuum FoMoCo unit has C5AF 12127 N cast into the body and the numbers 5BC under the C5AF number.
Click to expand...

Strange ... This DIST uses points and has not been converted to DS II?

The FoMoCo DIST is off a 1965 SBF. Dualing diaphragms were not introduced until the 1968 model year (IMCO Emission). You can convert to an earlier one diaphragm vacuum advance.

As for the shaft length difference(s), refer to this and see if it helps - https://www.onallcylinders.com/2020...l-pump-driveshaft-distributor-alignment-tips/

CHI-COM parts are like CHINESE food, have a meal and you are hungry two hours later. Same for sex. Horny again in two hours.

Keep us abreast ...
 
Thanks for the research/info.I'm going to initially run the knock off point distributor since I have it. Meanwhile I'll source a single canister vacuum advance unit, points, and condenser for the FoMoCo unit. When I rebuild the 302 after getting all the install issues sorted I'll swap in the FoMoCo unit. Something about the large cap look of the HEI long shaft distributor doesn't fit a SBF IMO but it its an option if the shaft length becomes a problem.
 
51504bat said:
Something about the large cap look of the HEI long shaft distributor doesn't fit a SBF IMO but it its an option if the shaft length becomes a problem.
Click to expand...

- GM HEI -​

But it will get a lot of stares and comments when you pop the hood ... :rolleyes:
 
There are a couple of different types of the diaphragms. Early types are adjustable with shims, springs and spacers. The nose/nipple end unscrews and that's where the shims and springs and spacer is. The later ones that are Sheetmetal were not always adjustable but replacements were with an Allen wrench down the nipple. The dual advance units actually worked pretty good in my limited experience. There was a temp sensor that sent vacuum to inner diaphragm during overheat conditions and sped up the idle to increase fan and water pump speed. I also have 2 78 Fords that the inner diaphragm doesn't even have a nipple, just a blank hole. I've known both since they were new. So not replacement junk. 5/8 oil pump shaft engagement seems about right. If original shaft they are very strong for there size, same diameter as the mighty 427's.
 
You didn't mention the year of your 302, but in '85 roller cams were introduced in Mustang engines. If you have a roller cam in your block, it requires a steel gear on the dist. instead of the cast gear
 
That's the good one. I worked in the former building of scientific diagnostic tune ups. In floor dyno. Guy was good. There was a lot of science to carbs and distributors. Never forget the sound of my car on the rollers and the speedo hovering around 120, the exhaust crackling on the house next door. A person can spend weeks trying something new everyday to get it dialed in with weights and cams and springs. Anyways, kind of rewarding when a youngster says "how you get that to start so fast, you just turned the key and it's running"
 
51504bat said:
Thanks for the research/info.I'm going to initially run the knock off point distributor since I have it. Meanwhile I'll source a single canister vacuum advance unit, points, and condenser for the FoMoCo unit. When I rebuild the 302 after getting all the install issues sorted I'll swap in the FoMoCo unit. Something about the large cap look of the HEI long shaft distributor doesn't fit a SBF IMO but it its an option if the shaft length becomes a problem.
Click to expand...
You might want to read this,possible solution. https://www.corral.net/threads/distributor-shaft-length.740149/#post-5493704 There is a rumor that Pertronix offered a long shaft distributor may want to call them it would have the small cap.
 
Fired the 302 today with a aftermarket short shaft point distributor. Almost 60 pounds of oil pressure at idle upon fire. I'll stick with the current distributor for the moment. But the Pertronix is an option if it is a small cap and long shaft.
 
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