A 1/2 ton truck can not be converted to a 3/4 ton at all. A 3/4 ton truck is completely different. (Side note: One of the great urban legends is a Toyota Tundra is related to a 3/4 ton truck) A 1/2 ton truck transfers the load from the truck to the wheel via the axle shaft because the axle housing bearing race rides on the axle shaft which is then attached to the wheel. A 3/4 ton truck transfers the load from the truck to the wheel directly from the axle housing using a larger bearing race between the axle housing and the wheel while the axle turns in the center without a load. Larger springs and frame combined with this stronger bearing arrangement make a truck into a 3/4 ton or 1 ton truck (ignoring solid front axle options).
The payload package Ford F-150 comes with a slightly larger axle shaft to increase load capacity but the bearings still ride on the axle shaft. The payload package comes with one more rear leaf spring, stiffer front springs, heavy duty shocks all around, and E rated tires.
I would not order payload package parts because you could not be sure the frame mounting brackets are the same.
Please note (disclaimer): I recommend carrying campers only on regular cab long bed trucks with the payload option (have I mentioned in the last five minutes how much I love my truck?
) and staying below GVWR.
In my opinion, options to consider:
1. The new Fords have interesting payloads because of the aluminum cab and bed.
2. One of the trailer packages, the "better one", increases GVWR and so payload. I have seen rear spring variations on the F-150 unrelated to the payload package and guess they are the higher GVWR trailer package. When ordering a truck, the screen always reports GVWR so as you change options see if GVWR is changing. The last model F-150 had a 7700 GWVR with the "better trailer package. Check the door sticker on trucks in the dealer lots.
3. If the camper is on the truck only a few weeks each year, air bags allow quicker changes in suspension stiffness and easy leveling of the truck.
4. If the camper is on the truck full time, many frame and spring shops will add a leaf to the rear springs and some vendors offer completely custom rear spring packages. New springs will give the truck a stiffer ride when empty while air bags can be adjusted.
5. E rated tires and stiffer shocks can be added.
6. 100acre... did an interesting rear suspension upgrade, message him to ask.
7. Limit truck modifications that increase weight and camper options to stay within your trucks capacity.
8. The brakes on my F-150 work great with the camper on full time for a totally stock truck.
9. Trailer mirrors stick out a lot but give lots of visibility, mine were dealer installed.
10. Switch to a 3/4 ton truck if you want to pull any significant trailer while the camper is on the truck. If you want to heavily modify your truck to go rough country then use a 3/4 ton truck. My springs are not stiff enough to bring 1 ton of camper down off a rock or ledge.
11. The 3.73 rear end is better for hauling a camper in the hills or mountains.
12. I have met two 100,000+ mile F-150 extended cabs with Hawks on full time with only rear spring damage and otherwise happy owners. Several WTW members reported switching from F-150 to 3/4 tons, generally folks with larger tires (rough country driving?).
If you are shopping for the new Ford F-150, what is the payload for an extended cab 6 1/2 ft bed?