Who has run a cam with more that a .450 lift? There are a few...What is better fro drag racers short or long duration?

 

I've been curious about that too. Pami makes cams up to .488 lift, and the higher the lift, the lower the duration, for whatever reason. I'd like to know more about duration, I mean the real technical specifics of it.

 

I'll take a stab at this without taking up too many KBs.
The longer the duration the less low end you will have. Drag racers run as much duration as possable since they need all their power up top

-Shortening the duration will yeild better low end - increasing duration moves the power to the top.
-Higher lift helps the top end power with little effect to the bottom end. This is why F-1 engines run short duration with astronomical lift. Obviously this is the direction most would want to go to have a good "do it all" engine.

The only factor limiting this type of cam profile is the strength of the valve train components. High lift-short duration action slams the valves open/closed so fast that conventional springs, valves and retainers can't handle the stress of the RPMs that this combination makes possable.
Cutting-edge engines tuners are using exotic metal combinations or even pneumatics for valve return force in order to achieve the ultra high revving engines that you see in F-1 cars and (now) bikes.
For us, this stuff just isn't available so we are limited to a cam profile that will allow our valve train to live.
What is the best combination? I think that remains to be seen though it looks like there are a few that are spending the huge amount of time with R&D to get there.
Problem is, the cam is only one factor in the set-up of an engine. You still need an induction/exhaust system that will work best with a chosen cam profile and RPM range.
The engine is only one factor in the proper set-up of the vehicle......