68 327 bellhousing ?

[NewKid]

This is a 3858403 casting, but has the 5 1/8" bearing mount hole. Is this an error or is this correct? I thought that this bellhousing casting number was the 4 11/16" hole instead.. But because this is a truck site and not a car site I thought someone might be able to clear this up for me. I was reading somewhere that said this was for the 11' clutch because it was out of a truck or high performance car. But because this is, I thought, was supposed to be a 4 11/16" because of the casting # and not the 5 1/8" that it is, did they have the same casting # for both sizes? the clutch that came with it is about 11 7/8" Thank you