I believe the ID of the crankshaft hub is 1.705". I think this is standard for all GM. Most afetrmarket cranks machine the hub to this spec. My buddy with an IHRA 800 " motor needed one and so I gave him the extra one I had for my SBC. Anyhow, I got it from Tim Mcamuis Race Cars (or try Quatermax (Rick Jones). It is a nice roller unit and not bronze.
Steve C