I recently bought a set of F9A Durabond cam bearings on eBay and discovered they consist of a wide, single-holed front, and 4 multi-holed center bearings. While I can see that this would cut manufacturing costs, thus making the parts more available, I wonder if the reduced surface area might promote accelerated wear in the 3 journals that need only a single-holed bearing? Has this been an industry standard for very long? (All my parts manual illustrations show 3 different types). Has anyone had a set of these long enough to gauge how they wear?

6 VOLTS/POS. GRD. NW INDIANA