You mentioned changing everything but plug wires. They're definitely a possibility when dealing with a miss under load. If it's a sharp loss of power, not a gradual loss and a surge back to normal pulling, it's probably ignition, not fuel. Try a new set of plug wires before you chase any more gremlins.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!