Upper left is from a 54-59 truck, upper right is from a 49-54 car, and for good measure the lower one is from a V8, I think its about a '59...
this view shows better the angle difference of the forks. Note that using the mounts after cutting the slot lower is probably unlikely. Wether a 48-53 truck housing would be any easier, I can't say at the moment...
I measured the pivot ball diameter on all 3 housings, and they were the same...
