Alternator

Sorry that I can't help you with that but I wanted to make you aware that this is the worst design generator ever produced and GM has no plans to improve it. It is real common to go through four to six of them in the life of the vehicle, but what many professionals are finding out is to reduce the repeat failures you should replace the perfectly good battery at the same time. These generators produce huge voltage spikes that destroy their diodes and internal voltage regulator. As batteries age, they lose their ability to dampen and absorb those spikes. That's where the new battery helps. Your old battery will work fine yet in pre-1987 cars.

As for that elusive bolt, if you have the new generator already, look at that one to find the mounting holes. Typically there are only two.

It is a difficult application. There should be one that comes from the back on the lower right side. Make sure and disconnect your battery before removing the alternator. I assume it is the upper left front bolt that you found. Hope this helps.