The B&C 60-amp alternator comes with all the hardware you need to mount it to the engine. I first bolted the (very substantial) mounting bracket to the matching boss on the engine:
The two mounting bolts get secured with safety wire, and you also bend up the tabs on the little washer-plate thingy to further immobilize them. Talk about belt and suspenders.
The included spacers put the alternator in just the right position to get the pulleys lined up. Here it's just hanging from the pivot bolt, as the tension arm isn't in place yet.
The alternator came with a Gates 7365 belt:
Oh boy, another little surprise… not only will I have to take the propeller off to replace the belt at some point in the future – probably a most inopportune time – but I also had to pull the ring gear to get the belt past the starter's pinion gear.
Here it is with the tension arm loosely connected. I think I'm going to go find a shorter belt so I can tuck the alternator in closer to the engine and farther away from the cowl.
I also had to replace the belt in our vacuum cleaner yesterday, so this has pretty much been an all-belt weekend.