I bought some underdrive pulley's (used) and was wondering if I can use the stock sized belt or do I need a different one? If different, what size/part number.

 

1. replace crank pulley with a SMALLER (underdrive) pulley = stock belt may be too long.
2. replace crank pulley with a BIGGER (overdrive example: 4,6,8-lb'er) = stock belt may be too short.
3. swap blower/snout pulley with a SMALLER one = then stock belt may be too long.

I assume your idler pullies and idler bracket are stock. Part#s & length will depend on which one above you're doing.

 

I would assume he is instead referring to the engine accesories

--Joe

 

Yes if you bought the set that I make.don't know about the 'other' ones thou.Stan

 

Yes, its a set you made. I give props where warranted. And these deserve props! High quality!