Very cool...
Jezebel is a bit older than '74, but I assume that the theory and principles remain essentially constant even with new Asiatic repops?
Wirespokes' comments, allude to my longheld theory that a certain amount of backpressure created by the exhaust "system" will yield HP benefits.
I'd guess that's what the skinny chamber would do...
Stagehand, on the other hand, has poo pooed the notion that my exhaust system needed to be "tight"...it's a/2!.. just stick 'em on there!
And between the crossover pipe and the "slip on" silencers, I assumed he was right....
This year, I've actually achieved some gaseous integrity, and though I've not many miles yet, it seems to have made a large difference in performance...better....
When I first got the bike it had a pair of beat up Sirwin's on it...loud as hell and straight thru...I think some PO put 'em on to improve performance...