Well I haven't (and most likely won't ever) port and polished the head of my TLD predator, but back on my Stroker Big Bore 400cc Warrior riding days, I sent the head to Powroll for documented port and polishing on their flow bench.

See the attached actual Data for flow gains and where they happened during the lift of the cam.

See the before and after CFM flow, at how much inches lift of the valve, and the number in the green box is percentage of gain.

Basically, porting really helped the gain of the Warrior heads intake track during low initial lift of the cam, and the exhaust side didn't gain much except towards almost full lift of the valve.

Stock Warrior Cam lift was .380/.382, and I jumped up to a high lift .430/.430" cam. and YES it really did breathe and pull better!

Pretty much it was a 5-30% flow gain.

Pretty pictures with facts and data here:

http://www.geocities.com/kiwi_craig/GRAPH.htm


I'm glad to always feed technical input when I've got the time to add my 3 cents worth. Thats what us engineers are for! Facts and data!

Enjoy.