i recently noticed that the B4V RPO vehicles (SS, VHO) have a different part number than the rest of the LS trucks. box and rack trucks take the same pump but the B4V doesnt... anyone know the difference? and im not talking about the 'towing pkg', which carries the same pump but different lines (includes a small vertical cooler on front left (driver) radiator support.

 

Hydro boost being the difference? Just spit ballin here . . .

 

The difference is how far the pulley presses on the shaft .

03sierraslt and myself ran into this problem when installing 8 rib pulleys on our trucks . I'm sure 03sierra will see this post and can elaborate if needed.

I don't think you will have a problem with the stock pulley .