Type S159 Distributor Bearings

I'm rebuilding my distributors on my 1975 308/GT4 and need to replace the bearings. Searching both sites I found that the top (outer) bearing (on the spider) is SKF 630/8-2RS7, but I could not find any reference to the larger bottom (inner) one. Has anyone out there found a cross-reference for that bearing?

Thanks in advance. (no pun intended)