One of the reasons for the work on the 140 at this time is that the water pump was leaking badly even if the radiator cap was removed to insure no pressure. I have the old pump disassembled awaiting needed repair parts. The radiator had issues also, so it went to the shop. Bad core. Shop sold me new radiator cheaper than a recore price. But new radiator uses smaller filler cap than does the old- and no cap was furnished. The radiator caps at Advance are pressure from 12 up to 20 pounds per square inch. I do not know if the 140 original cap is pressure style, but doubt that it would be that high if it was pressure. Maybe 5 to 7 PSI? I don't need more water pump problems!
So, is the original a pressure cap? What rating?