Why did Buick GS's 455 w/o air use a 37amp alternator and the Stage 1's w/o air used the 55amp? Was there a mechanical reason for this or just a nice upgrade?
Possibly so the alternator could keep up with ignition demand? If'n the headlights are on(big draw), heater fan is on(big draw), and WOT is demanded, a better alt would keep adequate voltage/amperage to the coil, to prevent ignition issues.
I would expect that the Stage1 would generally be run at higher RPMs. That being the case, maybe GM put a larger pulley on the alternator like they did on Corvettes? I don't know this for a fact, on Buicks. That is one thing I did on any car I hot rodded. There is a fair amount of inertia in an alternator that's spinning north of 20,000 RPM. One gets a little more acceleration if the alternator isn't spinning like a gyroscope. Since it is spinning slower, maybe GM wanted the higher amperage output alternator to make up the difference. [drag racer trick]
I would think a car with PW and seats and other options would get the bigger alternator regardless. Buick’s came “loaded” a lot.
My GSX is a stage 1 and had no options...except power steering and brakes...but had a 55amp alternator...so my Chevy buddy says they wouldn't put it on the stage 1s unless they had a reason...I told him not necessarily maybe Buick just put it on there for the heck of it! But who knows!?
Look at the relative size of the pulleys. If it is a 4:1 ratio (not far off the mark) an engine revved to 5k RPM will spin the alternator at 20k RPM. Go measure some pulleys if you don't believe me.
Stage 1 cars all came with heavy duty cooling, which consisted of all of the a/c cooling bits and fuel pump return lines. That's why the Stage 1 alternator, water pump and crank pulley are all dual groove.
