David, her are a couple of pics of my Autozone Delco-style 65 amp 3-wire (not one wire) alternator. Same alternator that would go on late 60s Chevys.
You will have to grind on the case a bit for it to snug up to the stock bracket on your block. I thing I had to grind on my stock bracket as well. Sorry to be so vague about where to grind but I pretty much eye-balled it, making sure that the pulleys lined up (used a yardstick and good eyesight).
You will see that I found a good stout bolt to fit between the alternator and the bracket. I may have had to ream one or the other so they were the same size. (boy, I am a lot of help here.) I used an all-metal locking nut on the bolt so I could loosen a few times as needed and the nut won't wear out. I went with a long bolt so I could locate it in the dark with a deep socket. Unfortunately, all I could find that fit the bill was a metric bolt (now I have a metric bolt on my TR6).
The next thing is go to any auto parts store and buy the chrome-plated universal alternator bracket that you see on mine. It <u>was</u> chrome but you will have to shorten it and grind on the lower arch for the fan to clear. Not a biggie, you will figure it out. I ground the rest of the chrome off and painted it.
The rest of the alternator support (that lower bolt is quite stout and is stronger than you think) is this bracket, which you bolt to the top of the alternator. I actually tapped the hole in the alternator and got the appropriate bolt to screw in, a little more secure this way.
I had to use the pulley off my Lucas because the pulley on the Autozone was 3/8", I needed 1/2". Use an impact wrench to take the pulley nut off, otherwise you will never get it off without busting something.
Get the alternator clocked to fit your wire location, they will do this at Autozone. Hit and miss on the pulley size, I just guessed, bought several and returned the ones that didn't fit. Then bought an extra for emergencies.
That's it.