hpalmer,
As suggested above, check the tie-rod ends, king pins, and steering arm/rod. Also, if you think there is looseness in the steering box, first try the adjustments given in the Shop Manual (they might seem complicated but are quite easy - get a small fish scale from Walmart).
In 1954, if a 1/2 ton truck came with the 4-speed transmission (from the factory) I think the steering column did not have the two bolt holes for the three-speed shifter collar (mine does not have the holes). I do not know if this was the case in 1953.
As mentioned above, the backfiring could be from incorrect timing, a bad vacuum advance mechanism, or bad vacuum line from the carb to the vacuum advance mechanism (sometimes people closed off the vacuum with an incorrectly installerd carb-to-insulator gasket), a leak in your exhaust line (anywhere between the head and the tailpipe, a poorly adjusted carb, or a carb with a bad float mechanism (dripping gas into the intake at all times). There are probably other reason but the ones above are ones I have experienced (and solved) in my two trucks over the past two years. One truck had a single carb/exhaust and the other had dual carbs/exhausts. Luckily I had a lot of spare parts and patience.
Good luck,
Tim
