This kit will work on all 1955-68 Small Block Chevy Motors With a "SHORT" water pump 

NOTE!! Will NOT fit Corvette Short pumps Or Early Chevy Trucks with 3/4" pilot shafts"
Kit includes: 

Nice Powder coated black Pulleys.

2 groove Short water pump pulley 

3 groove crank pulley 

2 groove KEY WAY style power steering pulley. 

Water Pump Pulley Diameter: 6.40". Bolt Circle: 1.75". 

Crank Pulley Diameter: 7.30". 

Power Steering Pulley Diameter: 5.75" 5/8" Keyed Shaft 

This will not work on early 265-283 with riveted on pulleys. 

To determine if your water pump is short or long. 
If your alternator is originally on the driver's side then it is a short water pump.
If your alternator is orginally on the passenger's side then it is a long waterpump.If you can fit your hand between the waterpump and the timing chain cover then you have a long waterpump.