Mr. Yuck you already know the answer to this, as most here. It would generally be easier unless your car is already set up for big block. But also for the sake of small block argument a 408 is simple and cheap to build and 550hp is easy with a w-2 or eddie head ported. I had one that ran 11.0s@122 on pump would a 440 run better? Maybe a little but when you gotta change headers, tranny, then no room for power brakes and steering the stroked sb can make sense.
