Distributor Vaccumn Advance

JJHstang

5 Year Member
Sep 12, 2018
204
11
18
Fort Worth, TX
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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I found the correct part and have replaced it .
I did learn 1 thing. Good idea I got from a video, 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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Good to see you got it fixed. Just an FYI if you weren't already aware looks like somebody swapped out the old points distributor and put in a Duraspark system. You may want to check your total advance (base timing+mechanical advance+vacuum advance. The 78 Duraspark coming off a smog motor will have limited total advance compared to the muscle era 71 points dist.
 
Good to see you got it fixed. Just an FYI if you weren't already aware looks like somebody swapped out the old points distributor and put in a Duraspark system. You may want to check your total advance (base timing+mechanical advance+vacuum advance. The 78 Duraspark coming off a smog motor will have limited total advance compared to the muscle era 71 points dist.
Any chance this vac advance is adjustable within the lock out slot limits? Many of the GM HEI replacements are adjustable with an Allen wrench through the port.