Feets , The plenum volumes and runner arrangments are different for the intakes. After building up a 440 intake collection, The 440 performer is much better than a CH4. A Weiand 8009 is a inch lower than the 440 performer and has similar characteristics(less mid range) to save hood height. That is from somebody who owns both, Heck, all of the single carb 440 intakes.

A dead spark plug should be very noticeable pulling on the rollers. The condition of tune should have told you not to wind it out at any rate.