If you are swapping in a 1970 or later 302-351 this eliminates the extra grooves for A/C and smogMARCH Two Groove Crank Pulley for 1970 and later 302-351W with 4 bolt balancer and driver side water pump.Part# 1631 This was only used for break-in and was changed out because I needed a 3 groove to run A/C.Price is was $89.95 from Summit plus shipping,$70 will include USPS priority mail shipping in the lower 48.
Strange, I don't have that problem just needed a 3 groove to add A/C.It could have been a minor misalignment problem I had that happen on a SBC added a thin shim to the water pump and that was the fix.I had a set of the MARCH pulleys on my 302 and took them off because I could never get the belts tight enough to stop squealing!