Hello im in the process or rebuilding my 250. Got my crank back from the machine shop and realized i didnt have a rear seal to put it in the block. SO i went to the local auto partsw and found out there are 3 listed for fel pro ?....First of all arent all 250 s the same till 1984 rear main seal wise or was it like SBC where they changed the crank journal size ?...Does this have any affect on me in the straight 6 issue ?...Also the three listed are a single lip, double lip, and offset, ive sorta concluded in research that the offset is a newer updated version, i think....Cna anyone assist in this matter ?
