Distributor vacuum unit

[ChrisinAZ]

I need to replace the vacuum unit on my '64 coupe (390 4bbl). Mac's Auto parts has 2 in the catalog - 1st is 58-64 part# 66-31323-1 $24.95 2nd is 60-66 part# 66-37105-1 $29.95. Anybody have any ideas which is correct? Do I just buy the cheaper and save $5? (Both are aftermarket and have a rubber vacuum line connection).

[Terry64HT]

Mac's part #66-31323 has an off-centered linkage while #66-37105 has a centered one. Most other suppliers list the centered one for 65 and 66 Birds and the other for up to 64. However, the 64's used a potful of 63 parts during early production, so, depending on your build date, it could be either. I don't know if they are interchangeable. You may have to see what you have.
Mine's a fairly early build 64 and has lots of 63 parts, making buying replacements a bit of a trick at times.
Good luck
Terry
64HT

[ChrisinAZ]

Thanks, Terry. I'll get it to pieces and see what it looks like. May phone MAC's and see what they say.

[ChrisinAZ]

The expert got it out - it's the offset one. So I can order now from MAC's. Much thanks, Terry, for the help. I'll report back when the bird is flying again.

[Terry64HT]

Glad to help. I've found that it's a good idea to check several of the suppliers catalogs because each has a bit different information. I even have an old copy of one from Nick's Thunderbirds, which is full of all kinds of information. I understand Nick retired a few years ago, but I would love to get permission to reproduce his catalog as a resource (possibly available here).
Mine is pretty old and dog-eared. It's seen a lot of use.
Keep us informed as to your progress.
Terry
64HT