Is sound quality, and thus marketing, the big difference? Does one create less backpressure than the other at the same flow? Or, does one affect scavenging more than the other?
Built this X pipe system for my 68 Camaro. The sound is higher pitched than with straight duals and slightly quieter.
I have never noticed a power gain or significant difference between H pipe, X pipe or straight dauls -- but I do like the fact that it tends to cut down the noise.
Supposedly there is a very minor scavenging advantage to the X pipe, but that is tough to prove.
Reduced noise can mean less restrictive mufflers which cam mean a power increase, however I doubt the "H" or "X" pipes alone gives any real power increase. Certainly not the 15% claimed earlier by one person.
Regards
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