There's an old adage that: "There's no replacement for displacement." In the case of a racing motor, that's 100% true. In the case of a street engine, usually not. Although I have the pleasure of having an OHC 6 in one of my cars, it's on its way out to make room for my 428. Why a 428 instead of a 455? I have a 455 in my GTO. It's a lot of engine - too much engine, in fact. For a street driven car, I should have left the factory 400 in there and spent the money on a good paint job. (I won't go into the engine details.)
Even with the cost of gas in mind, the on-demand power of a V-8 more than makes up for the increased gas use. Though a Sprint OHC motor offers excellent power for its weight, the V-8 still pulls a little harder off the line. (I'll keep the OHC around because it is a really cool looking motor.)
The 428 is a stroked 400. Stroke = More torque at lower RPM. Torque at low RPM is what makes a good street engine, not horsepower. The 455 is also long on torque since it's basically a stroked, .030 over 428. But, unless all that torque gets hooked to the pavement, it's a little bit of overkill (or a lot of overkill).
So, whatever motor is already in the car is always a good starting point - especially a 350 or 400. It keeps the cost down for a new engine. The only drawback of a 350 is the avaialbility of "affordable" pistons. The drawback to a 455 is constantly paying for new tires and more gas.
