I am going to use this thread to document the conversion on my SIIA hybrid.
The starting point is a 1968 SIIA chassis. With standard 88" axles. I am removing these, and am going to install 109" SIII axles, going Spring Over Axle configuration.
I will update and edit this thread as I document all relevant information, as a log of the build, and in case any future SWB owners want to try it also.
Follow up post:
The truck is sitting on a level concrete driveway, on a set of new 215/85/16 tires, on matched rims, and matched air pressure. All angles have been calculated to include angle of driveway, so are accurate to frame itself.
The starting measurements are as follows:
Frame, measured from the top flat surface;
Rear axle, measured over centerline; +1 degree, both sides.
Mid-Line, measured over transfer case crossmember; 0 degrees, both sides.
Front axle, measured over centerline; -1 degrees, both sides.
Rear axle;
Clearance to bottom most point of diff; 9 1/2 inches.
Clearance to bottom of spring hangers; 9 1/2 inches, both sides.
Angle of axle, taken off upper spring perch, between U bolts; -1 degree both sides.
Angle of pinion flange; +1 degree.
Front axle;
Clearance to bottom most point of diff; 9 1/2 inches.
Clearance to bottom of spring hangers; 9 3/4 inches, both sides.
Angle of axle, taken off upper spring perch, between U bolts; +12 degrees both sides.
Angle of pinion flange; +3 degrees.
Distance (length) of diff third member, from pinion flange to centerline of axle, both diffs; 10 1/2 inches.
