I personally prefer the sound of a H pipe over a X pipe, yes the x makes more power over the h but it depends on personal preference.
I'd run an H-Pipe with his set-up already... easiest/quickest & cheapest possible resolve
The dreaded drone, is
more than likely from too big of diameter, improper sized tubing/exhaust pipes, for your engines output/needs &/or not enough heat being developed &/or causing a resonance/reverb pulsation sound wave, in your exhaust... often blamed on or attributed to solely Flowmasters mufflers... the H-Pipe will help some with that too...
It's only marginally "
maybe a 1-2 hp difference" at best, over the H-Pipe & only if everything is absolutely perfect, the X-pipe or H-Pipe is installed in the proper position, with the proper size tubing for your exact combo... Right where the exhaust is cooling in the pipes, to draw the heated exhausted/scavenged charge pulses from the opposite/other bank...
I'll share a trick with ya' taught to me by an old S/S racer to figure out how long a header extension should be used when running open headers... there's an old trick; use some white shoe polish, put a line down the pipe from about 6" off the headers or where the pipe starts to run flat towards the rear {
if you have OEM cast iron exhaust manifolds}, go about 30" towards the rear of the car, from that with a good solid line of shoe polish with the little spongy head on it, let dry completely, now fire up the car, bring up-to about 3000-3500 RPM, hold it there for a 15 second count or so {
longer or slightly higher RPM if necessary, to get the discoloration & duplicate cruising speeds}, where the shoe polish starts to burn or turn really brown, begins to discolor the most, is where the leading edge of either the H or X-pipe should be correctly installed...
I'd bet you could NOT ever tell/feel the difference in Hp, between the H or X pipes... I've seen & read studies & comparisons both ways too... Believe what you will, but not everything you read in the publications/mags or on the www is real/true, they're selling parts for specific advertisers, a little biased sometimes too, it's the flavor of the month...
IMHFO it really comes down to your specific combo, it's not one size fits all & where it's installed in you system, to actually benefit from the crossover/exhaust scavenging...
That's my $0.02 cents, Happy Moparing
