I am in the process of rebuilding a 1965 mustang 289 automatic trans, and I have a question about which power steering pump I need to get to make it stock (I've lost the original). The one I've found has the small dipstick tube 1/2 in, but the old one had a larger one, (About an inch and a 1/4 in diameter). Did they use the smaller ones in 1965 or is the smaller tube one for 1967 and later. Thanks, Jim Fowler