[QUOTE=IJM;3724869]UPDATE:

I pulled the old alternator, trimmed the both brackets (aluminum and steel) as well as a tiny bit of the aluminum from the timing chain cover, and the bigger ACDelco 136-amp alternator fit in nicely. I did have to swap pulleys since the new one had an extra groove. Here's a video showing how loud the old one was. I'm glad I got it out of there before it locked up or caught on fire.

By the way, I pulled the old one completely apart, and I found the rear bearing was shot. That explains the horrid noise coming from the rear of the alternator.

So are you saying the 90 and 136 don't interchange without some chisel work?

 

Rumor has it that after the stock 117A, the case of the alternator is bigger and will not fit without grinding away some of the mount bracket. I had to do it way back when on my 92. Just for the record...my 2001 alternator harness has the 2 flat blade connector and not the 2 stud and ring terminal harness.

 

I just had my alternator die a week ago. Just suddenly got the chime and dash light and no charging. Went right to the field wires, disconnected them, and read 1M ohm across the field. Now, that can only mean either the field wiring on the rotor suddenly opened, or the brushes failed. I took it 3 places for testing , the first test at Advance just said FAIL. Didn’t text diodes etc. consistent with bad field, you can’t get much field current with 12v across 1mohm. Second and third places, it Passed! I’m like ok, come here you. Opened it up, which is incredibly easy 3 nuts on the back cover, and huge amount of black grime on the brushes, took the holder out and half a can of carb cleaner later looked pretty good, pretty good tension on the copper slip rings, and not even and deep gouges in the slip rings, so just cleaned every connection point with sandpaper and a file, assembled with No Ox paste, and voila, 14.6V I really wonder if most the low voltage problems with accessories might be just dirty brushes, after all are we reallly using 90 amps?

 

That's correct. The case of the 136 amp version is fatter, so it'll hit the bracket and you won't be able to get all the mounting holes to line up. I just trimmed off some of the bracket with an angle grinder, and it fit fine. I also had to trim an RCH off the cam cover.