[robnolimit]

the 'rake' on the upper arm, as to the pivit shaft, does creat the "anti dive". I am surprised to see that a lot of aftermarket IFS crossmembers have very little, or none. Remember that most IFS kits were built for 32-40 fords, copying must.II geometry, and these cars don't need much anti dive. They have good front to rear balance, and a low CG. Corvette stuff is also copied a lot, again, good balance and LOW CG, therefor, low anti dive. High anti-dive angles cancreate there own problems, as they create "caster gain" during suspension compression, and this can cause some bumpsteer.
So, back to the world of trucks. First, don't rely much on any geometryfrom the OEM pre-1988. ALL of these trucks were pure utilitarian. "Tractors with windows". Handling and ride quality were not too high on the spec list. How much anti-dive do you want now? I'd say 6 to 8 degrees total. That would be the total gain in angle between the UCA pivit axis and the LCA pivit axis. Now, since the LCA axis is basically level to the rail, you can set the anti dive in the upper mount.
The Guldstrand mod, or the Shelby mod, was simply to lower the UCA pivit shaft appx 1". This mod increases the amount of camber gain per inch of compression. Remember that these guys had to follow a certain set of rules for their class of racing, and OEM parts had to be used. Lowering the UCA shaft on a C10 can mean a lot of fab work to create clearance for the A-arm. Save you time and headaches, and buy some tall ball joints from Howe Racing, or Speedway. It6 gives you the same result.