Amazingly if you go though the parts books for say a 77 Chevy C 10 pickup there is only one spindle for short bed, long bed and crew cab. Check it out. Ackerman is nowhere as critical as some thing if you are not building a race car.
Not so amazing, as it's the steering arm that controls the Ackerman geometry, not the spindles. Here's a snip from the 1929-1957 parts book for the steering arms. You can see that there are different ones for the different size vehicles.
