12SI Alternator Pulley Compatibility?

[Rhodesplyr]

I'm working on a 1985 Chevy S10 Blazer with a bad alternator. This model uses a dual V-belt pulley on the alternator, but all replacements that come up online for this car use a single belt pulley. Looks like I will have to remove and re-use the original pulley on the new alternator.

Are most 12SI Delco Remy alternator pulleys swappable without running into problems with shaft length and thread depth?

One reason I ask is that this car originally used a 78 Amp alternator, but I can get a 94 Amp alternator in the same 12SI 3 o'clock form-factor, used in other GM cars from the same era. For example, the original on my car would be the 78A ACDelco 3342156A/Remy 20260, but the 94A ACDelco 3342193/Remy 20266 would also fit.

Thanks very much to any alternator experts!

[Stealthee]

Worst case, there are many electric motor companies that will rebuild alternators. This way you have all the same case and pulley. You could even have it "upgraded" to higher amperage while being rebuilt. This saves all the hassle of compatibility.

[j cAT]

my 84 berlinetta camaro had a alternator issue .. 78amp .. put the headlights on and the voltage dropped to 11 volts..I took it all apart looked good connections correct..
then I removed the diodes .. saw some green corrosion.. cleaned up the diodes and it worked perfectly...

now I had a lot of $$$ so I was gonna buy a new alternator that fits well I had to buy a rebuilt alternator .. I put 2 in and they did not work... so that is why I had to fix the 1984 alternator ....
I do not like rebuilt alternators ... and many have had failures on rebuilt alt..

[Stealthee]

Buying a reman/rebuilt from an auto parts store is very different than having a motor shop rebuild it for you. The shop here local to me that redid mine did it probably 15 years ago. That same alternator is still in my 3000GT. It cost me $80 to rebuild it, vs $200 to buy one from the auto parts store, that didn't even have any on the shelf anyway.