the big trucks are no longer than the small trucks from radiator support to grill. (I have a 5300 clip on my 3100 so dont try to argue)
As far as a 4BTA or 4BTAA, 300hp is max that you can get easily. The 6B variants can be pushed to well over 1500hp with the available parts as there is a much higher following
the 4B's do not have a balance shaft which is why they shake like a dog passing a peach pit. However you can run the front damper from a 6B to help (which is what they did with the Marine engines)
Long story short - Run what you want.