I ordered a new distributor for my 351 windsor. I don't know what year it is, but I am guessing it is around the 70's. When I pulled out the old point system distributor the hexagonal drive shaft for the oil pump came out as well. Upon further inspection I noticed that the hexagonal shaft from the old distributor is too small for the new distributor. Did I order the wrong distributor or did Ford make different sized oil pump shaft? And if they did make different sizes, is there a way to still use the new distributor or do I need to figure out exactly what year my motor is? Thanks.