I just peeked again at the Andereggen article and he appears to have assumed the front a-arm bolt is at the centerline. Based on my own measurements I'd say its real close but might not be perfect.
That piece of the suspension moves based on alignment setting and therefore isn't going to be perfect. That of course poses the question what will be perfect? And I don't have a good answer. You can measure carefully to find the center of the spindle with both wheels pointed straight ahead, but if you study the suspension design that centerline changes as the suspension moves up and down AND it changes if you adjust the alignment.
So the best you can do is get it close.
On mine I was struggling with how to get it close, and then noticed that each estimate of the centerline seemed to come very close to a pair of holes in the crossmember. These holes are near the motor mount holes and I had ignored them before. After identifying those holes I checked and they seemed to be square with everything and so close to the actual centerline that I chose to treat them as the centerline.
Compared to my ealier efforts based on aligning the wheels and determing spindle centerline using those holes, with a plumb bob suspended off a bar mounted on the original axle centerline with the bob centered in the holes, I determined my possible margin of error was less than 1/16th inch.
So I called it good and used those holes which I now consider alignment holes.
Andereggen never finished his truck with the IFS in it. He reached the conclusion his approach to mounting the steering box would result in bump steer and chose to start over with a new frame. Andereggen lives a few hundred miles from me and I was able to visit him and see his truck and shop some months ago.
I've only found one person who has performed this swap and still owns and drives the truck who I could see and talk to. He is nearly 80 years old and did the swap years ago. He lives less than 100 miles from me. One of his major points was that you have to be carefull to mount everything including the steering box in the same relationship they were in the donor truck.
I am aware of a second guy who performed the swap a couple years ago and still owns and drives the truck. He used to post here but has not been around much the last few years. This guy lives 600 miles away and I've not tried to see him. I discovered his location just a month after I drove within 100 miles of his home. If I get back that way I'll look him up.
I cut the donor frame just behind the shocks and have been using pieces of it as templates to locate the steering box and idler arm.
My weekend project is to complete the mounting of the steering box and idler arm. I'll probably post pictures eventually.
Andereggen's article is online at:
http://www.chevytrucks.org/tech/63-87_ifs_upgrade/index.htmHis measurements are for a 1/2-ton truck and would not be correct for a 3/4- or 1-ton.
