A well designed cam will make a huge difference. when I rebuilt the 235 in my 54 many years ago, I had the ignorance of youth on my side. I decided that I was going to buy all of the speed parts that I could find new. Iskenderian made 2 streetable cams for the 54 235. What they call the 3/4, and the "full race". They were both the same price. The spped shop that ordered it for may advised me to go with the full race as in his opinion, "buying the 3/4 was paying good money for an essentially stock cam". It is quite a thumper with a surprising amount of pull. It is a little lumpy in the idle department and will not be installed in the 261 when the time comes as that lumpy idle works against the hydra-matic shifting in my opinion. The irony is that the full race 235 cam specs are the exact same as the 3/4 cam listed for a GMC.
Point is, I think there is much that can be gained in a cam. But the name of the game is not just throwing more lift and duration. It is a balance between the two to offset design flaws in head design and valve limitations.
