[1972 Goat herder]

I am in search of the correct studs that attach the crossover (1972 455HO) to the intake/heads. I believe they are GM part # 483820 and identified as a 3/8" x 16 x 2 15/64" stud. (4 required). I have searched on that part Number (to no avail) looked at Fastenal, AMK, and two other Hardware distributors, but can't seem to locate a threaded stud with a tapered top (as shown in Pat's photo) - attached.

Does anyone know of a source for this type of stud. I am trying to be as exact as I can be in this restoration.

Thanks
1972 Goat Herder