[ratty69]

I think the answer depends on your long term plans for the truck. Except for the rear axle, is it stock? Are you planning to keep it stock? This is important due to wheel and tire choices.

If you're staying stock, with stock size/offset wheels and tires, then the narrow axle would be fine. There is lots of clearance as-is.

If you plan to go with larger, wider wheels with modern offsets, then clearance becomes an issue. They may not fit without spacers. The narrower the axle, the thicker the spacers/adapters needed. Ride height also affects the amount of room for tires, and where the wheels/tires need to sit to avoid rubbing.

Hope this helps.