[Rain Man]

I know this subject has been covered before but I need a little education on this topic. I have a fairly stock '66 L78 with the basic Hooker headers running through fairly quiet Magnaflows and 2 1/2" tail pipes. With no other changes will the X pipe perform better than the H design? What kind of power gain over the current setup with either design? Any other recommendations as to mufflers or pipe diameter?

 

[LXS]

If you're going from dual, but separate, exhaust, you'll notice a difference no matter if you go to an "H" or an "X" pipe. It's up to you which you really want to go with. A lot of guys prefer the H pipe because it has that sound they're looking for, while others prefer an X. I've got a muffler shop bent X that I'm decently happy with. The only thing I'd change if I had the chance to would be to get a mandrel bent X pipe. Mine has 2 huge creases (sp?) where the guy bent the pipes.

I know that you're looking to get the most hp outta your car/exhaust. But in reality, the few hp you get over the other (which I believe the X is slightly better), won't be noticeable in a street car. The best thing I can recommend is, look around at the track to see who's running an H and X pipe, and see which sounds better to you. Then go from there. Heck, and while you're at it, ask them how they feel about about their choice and see what they think about the other. Sorry, I know this probably isn't what you want to hear, just trying to help

 

[Olle]

As far as the power gain goes, I can tell you that I saw some improvement by installing a H-type crossover on my Camaro. Could have been about .05 seconds or so, but the major improvement was the sound level. The sound changed from a loud "thump-thump-thump" to a considerably quiter and more "Ferrari like" exhaust note (alright, that might not be what you all like...) Next time I buld an exhaust system, I'll definitely try an X-type crossover. Just looking at the way it works, I'd say that the X-type is better than the H-type. Most of the tests I have read about in the magazines say that any kind of crossover is beneficial, but it will also reduce the sound level considerably. IMO, it's a no brainer, it's a cheap fix and making it more quiet and at the same time gaining a few hp should be a great combination for any street driven car.

 

[Rain Man]

That's what I thought. I just needed to hear it from a first hand experience. My system with the Magnaflows is audible but not very loud and so I'm wondering if I could improve performance with some other mufflers since if I were to put an H pipe in there I'll be able to quiet down any new and better performing muffler.
Rain Man