The Stovebolt Site Forums The Shop Area Driveline Veers to right- bad steering geometry? Something else?

The last bug I need to work out on my 52 GMC 1/2 ton relates to steering. Some pertinent facts:
1. This truck had been in at least one accident in the past that damaged the frame in the vicinity of the second crossmember. I had to shim one rear motor mount.
2. I replaced the worn-out steering knuckle and steering arm with lightly-worn 3/4 ton parts from a parts truck. It all bolted together and seemed like a good idea at the time.
3. I added a 9th leaf to the front springs to try to compensate for using a heavier 270 engine. The vehicle rides about 2" higher than my other 1/2 ton trucks.
4. The steering gear is about used up and has no more adjustment left in it.
5. The axle is straight with no obvious twist and has equal shims under the springs on both sides.
6.The pitman arm is not seated as fully on the steering gear as my other trucks. No obvious damage to the serrations. Same pitman arm as other trucks.
7. King pins seem good.
8. All the other non-alignment factors in the shop manual don't seem to apply.

This truck was put together with primarily the best USED parts that I could obtain from several different vehicles. I realize that given this extensive list of potential problems, it would be difficult to remotely diagnose this particular truck from afar. The tendency of the truck to veer to the right is irritating but slight.

My most immediate questions on where to start include:
1. Is there any inherent problem with 1951 3/4 ton steering arm and knuckle ruining the steering geometry on a 1952 1/2 ton?
2. Is there an inherent problem with heavier 9-leaf springs and steering?
3. What's up with the pitman arm not seating fully?

I can retrofit this truck with proper 1/2 ton steering parts and a better used steering gear. But before I go and purchase these parts, am I on the right track?

Thanks, Dave