So i was thinking about replacing the stock pulley with something nicer. Right now I have a 2 groove water pump pulley. Right now my only accessory is the alternator, but I plan on putting in power steering, and eventually A/C.

My question is, the current pulley has 3 groves, does it require 1 groove for each accessory? Alt, PS, AC? Or can you use a 2 groove pully to run 3 accessories?

Didn't cars with an AIR pump, PS and A/C only use three belts?

It might be possile to make it work with two pulleys but it will take some bracket fabrication work to position things differently.

Then you get the fun of finding belts to fit your set up.

My opinion..... If it worked well and GM could have used a two groove pulley successfully, they would have.

honestly i have no idea..how everythign was routed since I had bought the crate engine there were no pullies. and no engine in the car when I bought it to refrence anything.

I dont have an Air pump, My final plan would be AC/Alt/PS so I was just wondering how many grooves each pully needed to I didnt buy something only to replace it later on.

I tried to cheat one time and use a two groove PS pulley to drive the alternator. It had a habit of throwing the belts. LS6 crate motor. GM would have used deep groove pulleys and wouldn't have A/C as an option.
It might have worked on a milder engine.

Not sure I'm answering your question, but on many v-belt small blocks they drive 3 accessories with 3 belts. That means 3 grooves on the crank pulley and 2 grooves on the water pump.

Inner most groove on the crank pulley drives only the PS pump (inner groove on on the PS pump). Middle groove on the crank drives the water pump (inner groove), A/C and outer groove on the PS pump. And the outer groove of the crank pulley drives the Alt and water pump (outer groove).

Three groove crank pulley is for AC cars
Two groove water pump and two groove PS pump pullies are for also AC.

Two groove crank and
One groove water pump and PS pump pullies are for non-AC.

My 78 had a three groove crankshaft pulley, a two groove water pump pulley and a two groove power steering pulley.

The inner most belt (closest to the engine) drove the A/C and went on the inner most power steering groove and the crankshaft but went behind (missed) the water pump pulley.

The middle belt went around the middle crankshaft groove, the rear most water pump groove, and the power steering pump.

The front most belt went around the first (forward) crankshaft groove, the first (front) water pump groove, and the alternator.

I have no idea why A/C was on a different groove than Damon's, maybe a different compressor or maybe my brackets were installed wrong by the idiot that owned the car (me).