Rear cam bearing options
Or, another option is to just use a die grinder with small diameter cutoff wheel and make a small trough in the bearing housing bore of the block, connecting the feed hole to the lifter gallery hole on each side. This trough, if sized correctly, can also double as an oil restrictor to the top end, if so desired. Then use a set of coated race SBC cam bearings in the engine. Do not drill any extra holes in the rear bearing; they are not needed now. The load capacity of the rear bearing is reduced because of the groove in the rear camshaft journal, but then it only has half the load of the center journals anyway. This setup worked fine in my roller cam 476, and I am using it on a 527 also. I tried to order the cam without the rear journal groove from Comp, but apparently the core already has the groove when they receive it. I agree, drilling the extra holes in the rear bearing will work also.
I also wonder if the brand new W-motor cam bearings that are available now are better than the NOS old ones, which we all know were weak.