My '66 122 is wearing a B-20 from a '73 140.

This is a real basic question.

I heard the familiar sound of a bolt coming loose and flying off the car while on the road. When I finally pulled over to see what it was, I noticed the lower "pivot" mount for the alternator wasn't connected to anything.

The bolt is missing and I can't see where it should attach.

Do the b-20s have a right angle adaptor bracket on them? When I mounted the alternator on the car last year I don't remember seeing an adaptor, but I'm not sure how else the Alternator would have attached.

Thanks!
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http://dylans122.blogspot.com

The B20 has a flange built into the block--maybe your bolt snapped flush and so the machined hole may be difficult to see. As you may remember, the bolt has a 3/4 head and has a 1/2 inch shank. The machined hole goes through the "flange" so if there's part of the original bolt still in there, it shouldn't be too hard to extract. -- Dave

I may be wrong about the shank size--could be 7/16.--Dave

No, you were right the first time! It is a ½"-13 UNC bolt with a 3/4" head.
Usually it is tight enough that it won't come out. It SHOULD have been!
Tighten the bolt AFTER tensioning the belt. (Can't tension the belt if it is tight.)
--
George Downs, Bartlesville, Heart of the USA!

Hmm, mine was 7/16 UNC - just did it yesterday. Maybe there are a few differences over the years.

Hello,

Just went through bolting on an alt, and went back to the old set up sort of...

I used the alternator bracket from a Saab 900 and cut it in half....
Why? Headers went in to replace the OE manifold.
So from the bottom rear and bottom front I attached the halved bracket- picture a capital D facing down... this allowed me to bolt an alternator and the original set up away from the headers and reinforce the OE bracket as well. Cheap, easy and effective fix.

Good luck,

greendread