I had basically the same problem on my 54. It took 3 people to apply the correct pressure and tighten the bolts to get the 1" gap to fit tightly against the cowl.
Loosen the hood bolts, both inside the engine compartment and inside the cab. Place a 4" block on the hood latch plate so the hood is slightly raised. With an assistant on each side of the back of the hood (basically standing over the hinges) they placed one hand on top of the hood near the wiper and the other on the side of the hood. (hands about 14" apart) #3 person is inside the cab with the wrench ready to tighten the 2 bolts inside the cab. The outside helpers press DOWN and BACK with their body weight while the inside guy tightens the inside bolts. Raise the hood and tighten the 2 bolts in the engine compartment.
Once you get your cowl area flat you can adjust your fenders on the core support to bring everything into alignment. If your front cab mounts or core support mount pads are missing or flattened excessively or your hinges are sloppy it will be tough to get a good fit.
I'd suggest you try this first before messing with shims under the hood hinges. Mine was visually terrible and after using the above technique it lays flat as a pancake.
Dave
