Joe -
First of all, if the 37 replacement king pins were too small, that makes me think you might have a 41-54.5 front axle under the truck. I say that because the king pins in those axles are larger than the 37 king pin.
Next, if this is the case, and you can tell by the casting number, you won't get the box to center up. In fact, I tried to center my 37 box up with the original front axle and never could. I have no idea why. I ran into the same thing with the 41-54.5 axle. When I did, I thought I had better put the 37 axle back under the truck and try something else. That's when I realized the 41-54.5 front axle is a larger, better, more heavy weight (beefier) axle, so I just kept it under the truck. I finally made an adjustable drag link. By using the adjustable drag link, I can center my box up perfectly. I tried a 54 car drag link, which is adjustable, but it was too short so I made a drag link for my truck. I used two tie rod ends and cut down an old tie rod. The same tie rods were used from at least 36.5 through 54.5, so they are easy to pick up at wrecking yards. I cut it close to the length I would need and rethreaded the right hand thread end. I was able to adjust it exactly where I wanted it by setting the wheels straight, blocking them and turning the tie rod, which adjusted the steering box where everything was dead on straight. It worked out great! You can even adjust it out for the crown in the road!
Hope this helps you out!
Joe :crazy:
