I've seen it done with Ford flathead V8's, probably because the exhaust system was dismal from a performance standpoint. It didn't matter how bad it was if you were using a blower and pressurizing the exhaust side of the motor and the intake ports make some pretty nice exhaust outlets. I can't see where there would be any advantage to doing it with a modern overhead valve motor, although you might tend to get some of the 429/460 guys to start leanin' your way. The weak point on those motors is the exhaust port arrangement.