rsg2506 - I did the same thing on my 37 and apparently Chevrolet didn't change anything from 37 to 48, because I found the same thing to be the case. Not only that, but the holes in the pitman arm and third (steering) arm are not tapered.
The only thing I saw that I could do was to put a bushing in those oversized holes and use the tie rod ends. I did it before I put the total assembley on the truck so I could torque down the nuts and bolts better on the bench top. I used castle nuts and used cotter pins on all the the tie rod ends. So far, it seems to be OK.