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The first series of dyno pulls with the 224/232-at-.050 cam (the small Cam “A”) sent the 347 into valve float at 5,900 rpm. SAM students busted out the valvespring pressure tester to discover just 110 pounds of seat pressure, and 240 pounds over the nose. To correct the situation, students shimmed the springs .120 inch, which effectively increased seat and open pressure to 150 and 340 pounds, respectively. This eliminated all vestiges of float for the rest of the test session.