72 350 Crank Pulley Diameter?

[69l46vert]

I'm hoping to learn what crank pulley is the right one for this 1972 GMC K2500 4wd 350 cu. in. No AC pickup. I have the power steering pulley but the crank pulley is missing.

Does anyone know the diameter, or even better, the part number? Or just something that will work?

I believe it to be a single groove pulley that is very close to the harmonic balancer but don't know the diameter. I'd like to keep the stock length belt.


Also I maybe should mention that it's the short water pump, Alternator and PS pump are on the driver's side. The existing water pump pulley is single groove.

Any help very much appreciated, Thanks!

[swamp rat]

First is this the origional engine? small water pump and alternator on the driver side?

If yes i can get that for you tonight, i work late but will look at my stash when i get home.

Its a 2 pulley setup that interlock's together.

[69l46vert]

Originally Posted by swamp rat

First is this the origional engine? small water pump and alternator on the driver side?

If yes i can get that for you tonight, i work late but will look at my stash when i get home.

Its a 2 pulley setup that interlock's together.

ThankYou SwampRat! Yes, original 350. Alt on driver's side. Short water pump.

[swamp rat]

Very sorry for the delay...

The diameter is 6 3/4"
Non AC pulley numbers:
Inner Pulley against dampener: 3751232
Front pulley: 3751232

I included a close up of the two pulleys together to show the way they are indexed via 2 raised hole flange's, note the pulleys go together one way only, this pic they are 180 degrees out, turn the top pulley 180 and the holes all match.

I have a set for AC i sat next to the other set so you can see the difference.

[69l46vert]

Thank you SwampRat for taking the time to check into this for me. Very helpful. Now I know what to look for. And thanks too for showing the AC pulley. This forum really is great, Thanks!

[swamp rat]

Your welcome and no problem, sorry i forgot when i got home late Friday night.