Don't worry it's not a speed-density EEC. The A9P is the EEC out of 89-92 Mustangs (5.0) equipped with automatic trannies. To be honest with you, your heads/intake/cam combination is way too small for the increased cubes of the 347. That heads/cam/intake is small for a 302. Your car is probably making in the 270-290rwhp range, with a boat load of torque (340-350 ft/lbs). You need bigger heads (AFR 185 or stage II TW's), better flowing intake (Holley is second to none) and more cam. Then, and only then will you see the benefits of the 347.
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TM88GT