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I'm really not trying to sound like a butthead, but you're wrong...it's "lopey" with more overlap because it's pulling in more exhaust into the intake manifold...I'm sure you've heard of "reversion"? Reversion has nothing to do with "pulling in part of the next fuel charge"...I've done it...it's not my opinion...it's fact...next time your motor is out, run it on a test stand with zoomies or short, block hugger headers and you'll see I'm right...




The air charge goes both ways. With lots of overlap, you get some exhaust in the intake manifold, AND you get fresh charge out the exhaust.

I agree that by changing header configurations you are going to change how the engine sounds and how efficient it is, and it will be most noticeable at idle, but to say the cam has no effect on idle stability is an incorrect statement. Fueling, ignition timing, cam timing, the intake manifold, compression ratio, accessory load, displacement, exhaust, etc...all have an effect on the "lope" of the motor.

'18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118