Distributor Vacuum Advance

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JJHStang

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My Car
1971 Ford Mustang Mach 1
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I have a problem with what Distributor Vaccumn advance I should purchase for my 71 Mach1 fastback.
The engine is 351W 4V. When it was installed replacing the 302 I have no idea.
My Distributor Vaccumn Advance needs to be replaced. There is a metal tag on my Distributor with the numbers D8AE-12127-JA.
I have not found a way to find out what the numbers represent but was told D = 70s, 8 = makes it 78, A = Ford (Full size like LTD), E = Engine
Group, 12127 = Distributor, JA is a revision/version.
If that is correct also told the VC-229 would be the part number. Found this one on eBay https://www.ebay.com/p/227924661. Very good price compared to auto parts stores. Also if not correct have to pay 20% restocking plus shipping.

Pics of current part attached.
 

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According to the 73-79 Ford Master Parts Catalog, the DD-794 is the correct vacuum advance unit for your specific distributor. Your distributor was used in the 1978 Ford full sizes, "mid size" LTD II and the Thunderbird with 351W engine.
 
I have a problem with what Distributor Vaccumn advance I should purchase for my 71 Mach1 fastback.
The engine is 351W 4V. When it was installed replacing the 302 I have no idea.
My Distributor Vaccumn Advance needs to be replaced. There is a metal tag on my Distributor with the numbers D8AE-12127-JA.
I have not found a way to find out what the numbers represent but was told D = 70s, 8 = makes it 78, A = Ford (Full size like LTD), E = Engine
Group, 12127 = Distributor, JA is a revision/version.
If that is correct also told the VC-229 would be the part number. Found this one on eBay https://www.ebay.com/p/227924661. Very good price compared to auto parts stores. Also if not correct have to pay 20% restocking plus shipping.

Pics of current part attached.
When replacing the vacuum advance diaphragm unit be very, very careful to not lose the little "E-Clip" that holds the are to the breaker plate. I always used a small magnet right next to the E-Clip when popping it off. If you are not familiar with what I am talking about be sure to watch a few YouTube videos where the folks handle managing not losing the E-Clip despite not taking the kid of precaution I do with a small magnet being right next to the E-Clip as I am removing or install it.

For what it is worth:::




Perhaps this Summer I will do my own video on how to replace a vacuum advance diaphragm, as the ones I have seen on YouTube do not say anything about being careful to take steps to not lose that E-Clip...
 
I found the correct part and have replaced it .
I did learn 1 thing. Good idea I got from the video to have a magnet. The thing I learned not to do was leave the tiny clip stuck to the magnet. When trying to put the clip back on was hard. The tiny clip had become magnetized. Every time my friend and I got it in place with small screwdriver and or pliers it stuck to the them and moved out of position. Finally got it snapped on. I would say it took twice as long as it should have.
 
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