Right off the bat your first problem is that the steering wheel is on the wrong side of the truck.
But seriously Michael, there is no simple way to make a 216 into a 235. Off the top of my head, I do not know the bore (diameter of cylinder where the piston travels) and stroke (the distance of up and down travel of the piston) of either engine, but the only way to effect cubic inch displacement "CID" (i.e. 216CID to 235 CID) is to increase the bore by machining the block or increase the stroke by changing the crankshaft. If the stroke length is the only difference then maybe a crankshaft swap may work but I do not believe they are interchanagable in these engines. Maybe an old babbit bearing 235, but not a more modern, (after '53) 235. And in my opinion it would not be worth it to attempt to upgrade to a babbit engine 235 even if you could find a crankshaft. You need to be instead looking for a 54 or newer 235 or 261 to swap into this truck if you are looking for more horsepower with an engine similar to the original.
The biggest problem you will have regarding going faster is the gearing in this truck. The easiest fix for this is changing the rear differential or swapping in a overdrive transmission or overdrive unit between the transmission and rearend. But as others have pointed out, you will want to upgrade the braking system if you are driving at modern highway speeds, especially if you have a load in the truck.
Finally, but should be first thought, do you want to restore this truck or upgrade it? If you want to restore it recognize you are dealing with 70 year old technology that will not perform to modern standards. If you upgrade it you will lose orignality. Its your truck and you should do what you want but I will say that that truck looks very original and in great shape for its age. It may even have its original engine in it which is extremely rare. If you want to do significant upgrades, you may consider finding a different truck to do so with and save this truck for a correct restoration.
Just my $.02, good luck,
Steve
