Alternator Pulley Shaft Size

19963.4lsr5 · 2020-11-04T11:30:43+00:00

Does someone have a spare Alt that they can tell me the shaft diameter? I want to try and find a different pulley to speed up the Alt at idle. The factory Alts (both the 70a and the 80a) are only capable of pushing 40a idling in gear at 600rpm. At 750rpm idling in park or neutral they produce enough to maintain system voltage with everything on. Sent from my iPhone using Tapatalk

Thread starter 19963.4lsr5
Start date Nov 4, 2020

19963.4lsr5

New member

Feb 4, 2024

_Ace_ said:
Will this fit an 80 amp OEM alternator?

I think that is what I have on my 1998.

No it will not. The shafts are different diameters.

I have an 80a that I freshened up and want to do it. However, I never took off the pulley to measure the shaft.

You may find OEM pulley specs looking at the 80a alts. DP electric or whatever they are called may have it listed.

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