Last Friday I got to visit with Joe at his place out in the sticks between Roy and Eatonville Washington. Joe is an older guy who winters in Arizona and about every second year drives to Maine where he visits his sister.
His travels were one of the reasons I had so much trouble finding him. But the interesting thing is
he drives his 1950 GMC with a Cummins Diesel and IFS swap when he makes these trips.
I started this thread looking for someone who had made the conversion and was driving the truck. Joe is the guy. He said he has driven it 90,000 miles since building it 11 years ago.
Joe and his GMC.
So the question is how did Joe do it. He emphasized that he had the front sheet metal off when he did the work, though I didn't get the sense that was critical. This is the only construction picture of the IFS he had.
IFS Construction Picture.
Joe is 76 years old and was talking about work he did 11 years ago. I felt he recalled details better than I do of things I did 1 year ago. He made spacers 11/16ths thick to fit the IFS to the GMC frame. He also put angle iron at the bottom of the frame to make sure it was stiff enough.
The same approach was used for the steering box, idler arm and sway bar. He said before he removed the parts from the donor truck he carefully measured everything and made notes to be sure it would be mounted in exactly the same relationships.
I wasn't clear if he was describing this project or giving advice how I should do it, but he suggested painting the floor, and using a plumb bob and sharp punch, mark the positions on the floor.
My suggestion to him was that I park the donor on a newly painted floor, straighten up and level everything, then set my marks.
Take the donor apart, and then park the new (old) frame over the top, aligning the centerline of the frame and the centerline of the axle with the corresponding marks on the floor.
Then mount the IFS making sure all the relationships are carefully held in place to prevent bump steer or alignment problems.
Joe said if he had it to do again he would narrow the crossmember instead of making spacers. His reason was that the tires stick out beyond the fenders even with custom wheels that brought the tires in more than an inch on each side.
I think that covers the details I collected from Joe. After hearing his story I'm much more inclined to make this swap on my own truck.
My thought today is to widen the fenders rather than narrow the crossmember. I like the idea of keeping the IFS as near its original form as possible. The road trip that took me past Joe's included attending Ron Covell's advanced metal working workshop where I watched him make a fender from scratch. Seeing that I believe I can widen fenders or at least I'm not afraid of trying.
Here are all the pictures I took Friday in their full high res glory.
Detail pics (broadband only!) 
