just depends where you want to go. to a point, building bigger inches doesn't cost anything more. stock stroke is 3.75. 4.15 crank will cost you the same (roughly) and get you 472 inches with the stock bore. now it is just up to you. what block you have, how far you want to take it.

my old motor is a 472, my new one is a 540, 4.25 stroke by 4.5 bore. i think in the end, the only real increase was the cost the machine work, (my block was a 4.19 bore, so taking it to 4.5 cost a few pennies more).

i haven't looked, but i don't think the cost of a stock stroke, 4.15 or 4.25 crank is that much different, if at all. rods are rods, and so are pistons, if you are ordering out of the catalog. custom is custom, and nothing here is too custom.

for a little or not much more, you can easily have a 540 over a 426.