Just thinking out loud,

TsNStangs · Post by **TsNStangs** » Tue May 31, 2011 6:30 pm

edpol:
I have come to the conclusion that the crossover in the H pipe improves the sound. I've been to shows that had Fords with 390 engines, with H pipes and performance mufflers that sounded much cleaner.

you need that crossover to help with exhaust scavenging.
That's what I was getting at. If I'm not mistaken, Magnaflow recommends an X-pipe when installing their mufflers. I believe it's either an improvement or an equivalent to H-pipes. On my car, I'm going with the H-pipe, and cutting the existing pipes to fit.

I think most all studies/dyno runs have shown that the H-pipe is an improvement over straight pipes, and an X-pipe is an improvement over the H.
I can say that - good or bad - in the cars I've added an H-pipe to straight pipes, the exhaust note has gotten noticeably quieter and "mellower", and added an almost imperceptible difference in low-end torque on stock or mostly stock engines (I'm speaking strictly on the butt-o-meter here, of course). My current '66 289 Mustang is one of them, and being a fairly low-key cruiser, the loss of sound wasn't really much of a problem, and was even welcomed, to be honest. Depending on your tastes or intentions, that might not please you.

VicRattlehead · Post by **VicRattlehead** » Tue May 31, 2011 8:16 pm

well it depends on the overall application, i know a guy that built like a dozen or so midsections for his exhaust and took them all to the dyno and swapped them out and dynoed it to figure out what one worked best. he runs the car in a dragracing series that i run in.

ive seen where the muffler has a big determining factor in what you use for the crossover H or X. chambered mufflers and straight thru mufflers like different crossovers. i cant remember what one works with what.

edpol · Post by **edpol** » Tue May 31, 2011 9:48 pm

I can say that - good or bad - in the cars I've added an H-pipe to straight pipes, the exhaust note has gotten noticeably quieter and "mellower",

I noticed that on cars I've seen in shows. With crossovers, the sound seems to be cleaner on cars with exhaust manifolds. Most cars with headers and no crossover are also cleaner sounding. I guess that's because properly designed headers are tuned. I've heard cars with home made headers that sound terrible.

Pete1325 · Post by **Pete1325** » Sun Jun 12, 2011 9:49 am

Well I cut out the round muflers yesterday. It's just straight pipes now with "H" peice and no resonators. The pipes stop about 2' from the rear bumper. She was pretty loud, not screeming annoying loud just a real nice rough grawl. I can really hear the H268 Comp cam in her now. She seemed a lot pepier or mayby it was just that I had my foot in the carb a little more to hear her run. I don't know what to install yet, Smitty's, Magnaflow, Flow Masters or Cherry Bombs? I ran her around the block a few times......good thing it was mid-day, it turned a few heads.

Dirty Birdy · Post by **Dirty Birdy** » Thu Jun 23, 2011 12:29 am

Here is a video clip of my car. Running FPA ceramic long tube headers into flowmaster 2.5" muscle car cross over kit into flowmaster 40 series.
Keep in mind motor also has a cam in it and the tips I think amplify the sound a bit too.

http://s122.photobucket.com/albums/o272 ... nt=046.mp4

Pete1325 · Post by **Pete1325** » Mon Jun 27, 2011 7:34 pm

DB...................sweet sound! What cam do you have in her? It sounds much different from my Comp 268H. Maybe it's the pipes.