A high quality aftermarket valve is worth the money for the increased flow and the insurance of it not destroying your engine. If you can't find any for your engine, have some custom valves made. Briggs valves are not high quality and will eventually break in a high rpm racing engine, and when it does it will likely ruin most of the motor. Just send the valves you have to Manley Performance in NJ, and they can copy your valves in a nice stainless or titanium, or make them custom to your specs. Just make sure you know exactly what you want to order if you want them made different than the stock valves (head diameter, lock grove location, overall length etc.) Last time I had them made the stainless steel swirl polished stem valves were only around $40 per valve, and i believe there is a discount if you order more than 5 valves at a time.
