I didn't say 'illegal' valve grind... I said 'legal' valve grind. The GCR states all rebuilding/machining must be per factory specs. The factory shop manual specifies a 3-angle valve grind and inludes sketches showing the angles, seat widths, guide placement, etc. The 'go fast' guys know how to cut the seats & valves to meet these specs, yet allow the tolerances to stack up in their favor to make the most power. In reality, the closer you can follow the factory shop manual specs, the more power you will make.

Here are two links to a website that has the manual posted. I posted the two pages that describe the valve grinds:

http://www.redpepperracing.com/technical/8...v-fsm-chap6/aap
http://www.redpepperracing.com/technical/8...v-fsm-chap6/aaq

Like anything else in the engine, you can legally blueprint the motor to the factory specs/tolerances. Another example...you can legally skim the head up to 0.025" but not to excede 0.5 CR point over stock. For this particular Honda engine, you can't take the full 0.025 of the head or else you'll exceed the CR limit. A good shop knows how much they can take off (and no, I don't no how much that is but I'm guessing somewhere around 0.015" or so).

What you are really paying for is the knowledge & experience in knowing when to go to the high side of this tolerance or the low side of that tolerance, in order to get the most power. Like anything, there are usually some tradeoffs. For example, in exchange for more power, your motor might not live to see 100K miles. It might have to be 'freshened up' after 3-5 years of hard racing, depending on how many events you run per season.

[This message has been edited by Greg Gauper (edited December 08, 2004).]