I have a 1985 D-150 with an 8 1/4 open axle, big bolt pattern, and a 1981 D-150 parts truck with a 9 1/4 sure-grip, small bolt pattern, I would like to swap the 9 1/4 into the '85, but retain the large bolt pattern, are the 8 1/4 and 9 1/4 axle shafts interchangeable?, if not, what do I need to do to my early 9 1/4 to get the big bolt pattern so I can re-use my aftermarket big bolt pattern wheels to work?