ok, for sake of talk here...

lets say i have a 99 silverado z71 ext cab with 5.3 auto. what alternator should i have? or is there a way to find out?

next, same question for a 2000 suburban with 5.3 4x4. has front /rear climate control..power options...

would it be the same alternator between the 2?

thinking of swapping the alt from the burban into the silvy and so forth...curious if the same or not.

 

there are to different amp alternators not sure how to check my truck is fully loaded it has three wires going in the top plug my brothers only has one that might be one way not really sure

 

There are at least two different alternators; The basic stock version is rated at 105 amps. The one above that is 130 amps. (Quadrasteer trucks had a 145 amp version)

Anyway, the 105 amp alt's case diameter is about 5 1/2 inches and the 130 amp is 6" in diameter. The mounting holes are the same.

If the alternators are both 5 1/2 inches, they're probably the same amp rating.

If one of your alternators is larger and you intend to swap it, make sure you move the belt with it. The larger alternator has a slightly larger pulley so it needs a slightly longer belt. Don't ask how I know.

I hope this helps.

Nick