440 w/air /PS-CrankPulley-4 groove or 3 groove?? Diff?

Just trying to figure out what the difference in the uses are for a 4 groove or 3 groove crankshaft pully are???

I have a 440 with stock altenator, cast iron crank with stock balancer, will have A/C & PS..... Why would I need a 4 groove crankshaft pulley?? or why not?? Could I just use a 3 groove?

planning on buying an aluminum pulley pictured.....

Factory air cars used a 4 groove lower pulley
2 for the a/c and alternator
1 for the power steering
1 for the idler and water pump.

Most Big Block setups with A/C and PS use 4 groove pulleys , 2 on A/C and alt. , one for the PS, and one for the water pump. Now if you could somehow get the water pump and the PS on one pulley you could run three , only see that setup with smallblocks though , but it may be doable on a BB .

Thanks for the quick response.....

I was on CVF Racing site and they have a set that says for A/C & PS but it only has the 3 groove crank pulley.....that's what is confusing......
http://www.cvfracing.com/chrysler-big-block-pulleys-s/45.htm

Big Block Mopar Engine Pulley Selection Chart (BCRL Series)

Pulley Kit
Water Pump
Crank Pulley
Alt Pulley
Application

BCRL3KIT
2V
BCRL2WP
3V
BCRL3CR
1V
SCR1ALT
Alt, PS & A/C



Also.....shouldn't they have a 2 groove for the Altenator??? I know a 2 groove for waterpump is what I need......



..

What year car are you working with? What are you using for an A/C compressor? Some waterpump setups use a one groove pulley and it's a belt with an idler all by itself, the PS will be all by itself also, alt will have a double pulley and connects to the A/C pump.

Thanks all for the help.....FINALLY decided to just go without A/C .......lot less headaches and money......lol