I'm just wondering if flat faced valves will do anything other than raise the compression a slight bit. Is there any benefit of having them?

Also, running an agressive cam profile, and using the flat faced valves. Would one encounter valve : piston clearance problems (Standard size)?

 

Piston-to-valve clearance issues won't change b/c of the face of the valve.

They'll contact the leading edge of the valve before anything else.

Valve diameter dictates piston-to-valve clearances.

There might be something to talk about in theoreticals on intake charge tumble/swirl and burn characteristics and optimization, but practically-speaking I don't know of any significant benefit to that aspect alone.

Maybe it's just easier to make the valves flat-faced and that's why they come that way.

 

Flat faced vales flow better than dished face on the exhast valve side.Flow going towards the exhast valve will react like a spoon turned face up under water. Flat faces have a much better smoothing effect on the air as it exits the chamber.

 

One disadvantage that comes to mind is the additional weight of the valves. With all of the individuals dead-set on running Ti retainers on their high-RPM setups, using heavier valves seems somewhat contradictory.

That being said, I don't know the exact weight figures, and there would probably be no problem running them on a moderate setup with the proper springs. I may infact look into these in greater detail for use in my brother's setup. Combined with a thinner headgasket, they would be a relatively easy (though not altogether inexpensive) way of boosting compression somewhat without touching the bottom end or sending the head out. When all is said and done however, I think the cost/benefit ratio will rule them out.