How do you figure if you have .120 of clearance with a .550 lift cam and you want to step up to a .650 inch solid roller I think lift would play a pretty crutial role wouldn't you?
Because piston to valve clearance occurs at the period of overlap.
It is when the exhaust valve is closing and the intake valve is opening, therefore, both valves are open at the same time when the piston is at top dead center.
Peak lift occurs when the piston is a good 1.5-2.0" in the bore.
Lift is not the factor, but probably the last factor to even consider.
Why would you want the valve to open up fully when the piston is near the top of it's travel? That would be very inefficient.
You would want the peak area of flow out of the head, past the valve, when the cylinder has the most volume to fill. It would not have any volume to fill at top dead center.
A stock camshaft would hit if it had late exhaust closing and early intake opening events with a steep ramp rate.
You also want more clearance on the exhaust side for a few reasons...
Juiced - I really wish you would work another couple hours and just spring for a $325 custom camshaft. He will even do all his business through emails if need be.
I personally believe the N-71 can be beat by a custom camshaft for just a little bit more money and you could have a more useable powerband.
The fact that you have Ed's PS3 valve springs gives you an edge already.
You will see your power output increase enough to put a big smile on your face