Thanks for the explanation between the “99” and 99a” oil pumps. My problem is the numbers are completely different from what the on-line HD parts manual list as being the correct oil pump and cam plate for my year and model. The part number stamped into the pump is 26299-99a. The parts manual calls for a 26035-99b and camplate part number is a 24255-00 and parts manual calls for a 25267-99B. I don’t know enough about Harleys to know if these parts are interchangeable or updates made over the years. I have done internet searches of all four numbers but can not find anything as far as fulfillment of the parts. Only that some are only available used on E-bay. My concern is that sometime during the lifetime of this bike is someone could not get the parts that the HD manual called for and put the parts in that are not compatible for this year and model. I once had to use the starter from a GM truck in my 75 Corvette, but in that case the part numbers where the same the only difference was the truck starter had “HD” after the part number making a “Heavy Duty” starter, which actually was able to start the Corvette easier then the one that was recommended after a engine rebuild. So I understand that sometimes parts are interchangeable. But I would have thought the first part of the number would have stayed the same and a suffix added.