Recently I posted about having problems installing my distributor. Turned out the shaft wouldn't engage the oil pump. I pulled the pump and the dist. drive shaft and the shaft looks fine, but it will not go into the pump. I looked at everything with a 10x magnifying glass and it looks fine I had a new Melling's M-63HV pump sitting on the shelf and tried that and the dist. shaft fits fine Is there any reasons why a high volume pump shouldn't be used on a relatively stock 440