X pipe H pipe or side by side

famous bob said
me thinks these things work better on smaller engines. but, a 68, 426 hemi roadrunner came w/ an h pipe on it ! over 500 cubes , I still don't think their worth their weight, provided your whole exhaust system is big enough! . jmo

And how much do you think a 6" piece of pipe weighs? C'mon. And actually the bigger the engine the better the effect, as the exhaust needs to be bigger, so too will the scavenging effect.

ir3333 said
We were discussing scavenging,tuned Try Y,optimizing lengths,volumes,diameters
how 2 into 1 compared to 2 into 2 could work with some excellent analogies.
...Now we are "new Mustangs have them" , "Nascar run 9200 rpm" and "Hensley got
20 hp", that's O.K. and suggests they work but we stopped trying to "figure out how"

We didn't stop trying to figure out how. I just dunno how many more times I can explain it to you without you getting it? What about it are you not quite understanding ir3333?