Testing has show for a given intake profile they will give a little more power with a longer exhaust duration. so lets say a standard 236/236 @ .050 110 LSA cam changing it to a 236/244 @ .050 cam will give a little more power and not effect the drive ability from where it is. the norm seems to be 6 to 10 more on the exhaust to get rid of that expanded hot exhaust charge.