For a high-performance street car, at a minimum you want a precision, three-angle valve job with relatively wide seats able to stand up to years of hot rodding. Quickie parts-store valve jobs won't ...

During one of our never-ending technical discussions, Jim Grubbs at Jim Grubbs Motorsports (JGM) suggested that we take a look at the flow difference between 30- and 45-degree valve seats. While ...