[Mr70]

To answer a few PM's @ once...
In the Chevrolet family:
BC,BE,BW,BK,BO,BJ,BQ & BR radiators all shared the same Harrison IA driver side tank.


BC,BW,BK,BJ,BR shared the same Harrison XP passenger side tank with an oil cooler,(Auto.Trans.)
The 4 core PD radiator did too.(Auto.Trans.)

BE,BO,BQ, shared the same Harrison XJ passenger side tank w/o an oil cooler.(Man.Trans.)
The 4 core PA radiator did too.(Man.Trans.)

The 4 core PA & PD used IF Harrison driver side tanks.

It was the size of the cores & their cooling fins that were different among them.Other GM vehicles used these same tanks too.