I'm running the Purple Stripe .474/.471, 280 duration,....340/6 4spd 3.91 gears,...the motors dynoed 443 HP usual goodies in the rebuild, 11 to 1 compression revs freely to 6500, but I try to keep it under 6000,....this cam/engine combo comes on strong around 3000 RPM on up,...not bad idle, rather choppy, I idle around 1200 RPM, but it sounds more like 600RPM, it that lopey I run a Mallory YL dual point reverse rotation Marine distributor with mechanical advance that holds the advance plate stationary until approx 2000 RPM, the advance plate is keyed for 28 degrees all in by 2000-2500 RPM, I run 10 BTDC initial, this set up gives the motor a good launch off the line, really puts the power down fast

Mike