Nice looking engine. You can do the pump work yourself and improve it for your application. The B oil pump had a turned down shaft to allow for more flow. You can do that with a Model A shaft. The biggest thing that will help the stock pump is to lap the gear cover flat, flat. that and make sure that the gears are the same height and just below the height of the housing. Maybe a half thousandth of an inch. I use gasket maker and seal the cover to the housing without a gasket...the less bypass around the ends the better. You can open the inlet to the gears too. Open the outlet. Make sure the outer shield covering the pock up screen, is sealed to the pump body. If it leaks the pump will suck air if it above the oil level. This is a pump that I put together with the inlet on the bottom plate, like CAT does their pumps. It has early V8 pump gears, hence the spacer and the relief tapped into the pump. I used a 90 degree street ellbow and the pressure relief is a 35# from McMaster Carr for an air compressor. My belief that a higher capacity pump puts more oil thru the engine and into the dipper tray for the rods if you stay dipper. Sustained operating above 3000 - 3500 RPM will empty the tray...can you say overdrive?