Hi, yes there are a few things to be aware of when moving from the Bosch AL64 to the AL69 with internal regulator. Sorry this is long but since it was recent I remember a lot, hope it helps.
The AL69 has only two mounting holes vs. three on the AL64, but only two were ever used anyway so it becomes obvious there is going to be only one way to make it work mechanically. The "long" hole is on top with the AL69 so a longer bolt will be needed on top to reach all the way through, but thats easy enough to pick up at HomeDepot. I suggest comparing the 360 degree view of each alternator on the Summit website I sent a link too earlier. That way you can see the differences in the body styles of the two alternators very clearly. Also I'll add a picture of my AL69 as mounted so it should be easy to see differences compared to how yours is mounted now. Bosch's website also has some good pictures of each, plus schematics for wiring diffs that I referred to, not plug-n-play but easy to adapt wiring.
The AL69 comes without a pulley but it was easy to pull the one off the AL64 and move it over. I also ended up changing the belt to a slightly different size so that the new alternator could sit in the best condition. Hard to describe in words but when you get it in there it will be obvious that it needs to sit in a certain spot for best clearances and with the way the mounting adjustment works that position is determined by belt length. I just noted the belt size on the old belt and could tell I needed to add a little length to get it to the best spot. Just went to the local auto parts store and asked for a slightly longer belt. The guy just stared at me and asked, for what? a lawnmower? Everything is serpentine belts these days, nobody asks for V belts anymore. The old timer behind the counter dragged one up, but if you have a problem just go to amazon where I bought a backup. I settled on this : Goodyear 15328 V-Belt, 15/32" wide, 32.8" Length
The AL69 is a bit deeper and leaves less room to work with the wiring. I said above that it gets close to the manifold but thats wrong as you can see from the picture. The main output lug does get close to the thermostat housing mounting bolt and the idle air hose. I had to remove that hose while working on it. I suggest having all the wiring worked out and terminated properly before installing the alternator so all you have to do is hook it up. Realistically you'll probably have it in and out a couple times to get all the mechanical mounting solid and tight. I had to rework the cable on the output lug a couple times because I added a hefty additional wire from the output over to the battery directly, which you can see in the picture with the heavy red heat shrink on it.
If you want to keep the original 3 prong regulator plug to maintain original wiring just in case you ever need/want to revert, then you'll need to harvest the socket from the old AL64 and use it to build an adaptor cable to go from the harness plug over to the new AL69 which doesnt use a plug/socket. The internal regulator on the AL69 takes care of itself but you still need that alternator wire going back to the dash, and thats really the only wire of the three which would have gone to the old external regulator. I also added an additional 8AWG ground strap from the alternator case to chassis ground because I was really trying to reduce voltage drops as much as possible and didnt want to depend on the the different alternator mounting scheme for the ground return. Maybe overkill, but I'm also sure to get max voltage possible over to the battery now. This is not a bad idea for any alternator type on our type of car. Cant hurt anyway.
thats all I could think of for now but dont hesitate to ask any questions. This was a fun upgrade.
