single groove crank pulley

I `ve seen advertisements that state,the small block crank pulleys are the same as a big block, anyone know about this?

I need a single for a 440, but don`t want to pay big bucks for it. can be had (new) from 440 source for $40 some thing------------just sawondering.:coffee2:

Going from a small block to a big block one of the holes is off just enough that you can't get the bolt started, file it just a bit and it will work fine.