Jpar the reason I asked and I did it myself years ago is just jumping up to a bigger valve should always help but proper sizing is needed. Throat sizing under the valve is often overlooked. The throat on an intake valve should be 88-91% of the valve size. Some guys push this figure a little but if you lose the venture effect (speeding air flow) exiting the valve, you trash the head. To small and you lose available gains.
