alternator swap, retaining 1974 brackets, belt? using new pulley with Delco

I've searched and read up.

I understand I will have to grind down an alternator case to around 1" to clear the AMC upper bracket, and probably pass a drill to enlarge hole.

The the Delco 10/12 swap, can I retain my lower AMC bracket? References to AMC cars show bracket replacements.

I probably am best with something clocked at 9 for this?

from: http://www.madelectrical.com/electricaltech/delcoremy.shtml
10SI, 63 amp, at 9:00 (AC-DELCO # 321-41, Lester #7127-9)
Tell the auto parts counter person that “The alternator is for a 1979 Buick Regal, 8 cylinder 4.9L (301W) engine, with air conditioning.”
The the Delco 10/12 swap, can I retain my lower AMC bracket? References to AMC cars show bracket replacements.

Is there a belt change required? If so is the part number handy?

I'd like to swap out after hearing the faint sound through the steth today of the bearings starting to knock on the door. I'd stick with the motorola to stay original, but I'd like to get up to about 55-60 amps, even if it means bypassing my 60 AMP ammeter gauge, which I'm sure many will argue for with even my current alternator and the aged wiring.

I know this is a beat horse around, I mostly am curious to agreements I can find on clocking at 9 and if I can keep my lower bracket. I'd like to try and address this Saturday and have what I need on hand.

 

update.

I got a great deal like 125 shipped on a powermaster in black since they are ditching the all black ones. It's got 1" ears and probably the most minimal tinkering for a replacement.

from what I understand some possible elongation of the the lower bracket slot.....

 

Replying to another super old thread to provide some clarity for the next guy. My '74 came with a 10si on the 304 that was making some unhappy sounds. Additionally the mounting tabs weren't ground square so belt alignment was a little funky. When I did my 360 swap, I purchased a replacement 10si for a 1978 Jeep Cherokee w/a 4bbl 360. It came clocked at 9:00. To modify the mounting tabs/ears, I held it in up to the bracket and rough marked with a sharpie, I did the initial conservative cuts with a hacksaw and then fine tuned with a grinder. I worked slow, grinding some, then checking fit, etc. I had the luxury of having the mounting brackets on an engine on a stand next to the workbench which sped up the process. It was easy/quick. See attached pics for the upper mount. For the lower tab I just took about 3/32" off of the forward facing side to get alignment. As you can see in the after pic, I should have taken the fan off - I nicked the edges of a couple of blades.

Hope that helps someone down the road.