300ex OS Valves

[rooster300ex]

How come you can get oversized intake valves but not exhaust. I mean if you got OS intake valves wouldn't you need bigger exhaust valves? makes sense to me.

[zeppelin]

intake valves are always bigger than exhaust valves, i would think that the reason they dont offer OS exhaust is because you would get more benifit from making the intake so big that you couldnt fit bigger exhaust,then you would if you increased them both