467-Ratman

I am building by 454 motor and it is going to have Hooker super comp headers to use with my aluminum pipes and V-Force mufflers. Question is do I need a H-pipe? Some guys say that it makes more power and is better balanced......Thanks for the input.

lars

Tom -
A good, free-flowing true dual exhaust system works pretty good by itself, but an "H" pipe or "X" pipe does, in fact, increase bottom end and mid-range torque, and this is what you want in a street engine. I've run engines both with and without an "H" pipe, or "balance tube," and you can actually notice the difference with the tube installed.

Good place for the tube is right aft of the forward driveshaft U-Joint. The tube, thus, acts as an effective driveshaft safety hoop (although not NHRA legal). In this location, you cannot install a straight piece of tubing - rather the tube needs to be somewhat "U"-shaped to fit properly. A good custom exhaust place should be able to fit one in for you with no problem. Also, the balance tube does not need to be the same diameter as the rest of the system, since it only sees pressure equalization and not significant flow.

mountainmotor

I agree with Lars but with those 3.70 gears you are never going to see midrange unless you are on the hiway at say 50 mph and put it to the floor in 4th gear.

467-Ratman

Thanks for the info, looks like I will be talking to my friends at the Muffler shop for a H-pipe.

Lt1er

It has been my experience that it's a great sound dampner. You double the frequence out of the pipes.

gerry c

While I do not have an H pipe on my vette, I do have one on my GMC 3500 truck with a 454. When I had it installed, noticed more on the bottom and midrange power. Important on a truck pulling a 10000 pound trailer.

no_radio

Definitely do it...when I had new pipes installed on my '76 454 Suburban to go with the new headers I asked for an H-pipe. Driving it home it was noticeably louder than I had expected, so I looked underneath when I got home and there was no H-pipe. I went back and the muffler guy tried to tell me there was no difference...I knew better and made him put it in. WOW, it was much quieter, better bottom end, and more mellow tone out of the tailpipes. It was such a difference that I went and got the Corvette (SB with headers and 2-1/2" chambered pipes) and had them install one on it. Again, HUGE difference, especially with the sound. My friends used to hate the exhaust rasp of my chambered pipes, now everybody seems to like the "new" sound.
I paid $15 to have it added to my '74 Corvette, definitely get one on yours!!
Jeff

vettesite

Worth every penny on mine! :yesnod:

PatsLs1vette

since ive installed mine the exuast resonance i was getting at low cruise speeds is almost eliminated ..

Jvette73

H-pipe is definatly worth it. The drawback can be that it can make driveshaft removal difficult. Has anyone ever connected the pipes where they come close togeather under the diff? It would take just a short piece of pipe to balance the mufflers there. But they do say the closer to the engine the better.

PatsLs1vette

jvette73 your right about the driveshaft removal i mounted mine just alittle too far back and when i was under there the other day i noticed im gone to have problems getting the driveshaft out. :( cross that bridge when i come to it.

Jvette73

To pull my drive shaft I need to drop the exaust and crossmember in one piece while the tranny is supported on a jack. Furthermore, since I have the closed end front yoke, i then need to loosen the rear crossmember to frame bolts as far as i can with out it falling out. Then remove the front diff mount bolt and pry down on it and chock it with a chunk of wood. This allows me to push the rear part of the driveshaft back above the pinion so the front yoke will drop down and pull it out. Its a bugger I'll tell you. :smash: :crazy:

PatsLs1vette

then im screwed because my frame(684speed) i replaced with a nonremovable crossmember and i have an automatic too..well i guess that custom crossmember is soon to be in the works sooner then i thought :yesnod:

jimduchek

The H-pipe does better the farther it is towards the engine. An H-pipe that is run between your exhaust TIPS wouldn't do ANY good at all, and if you could put it right under the oil pan it'd be best (but, obviously, that's not going to happen). Also, an X-pipe is better than an H-pipe (due to the fact that H-pipes, while no significant flow goes through the equalizer, do cause turbulence in the flow due to the right-angle). X-pipes are more expensive though, as they can't be 'rigged up' by an exhaust shop -- an X-pipe piece would have to be bought, fitted, and welded in.

At any rate, my $0.02 worth.

Jim

467-Ratman

Thanks for all the good info, sounds like an X pipe is the way to go. Will it make the motor less ratty sounding? I don't want this engine to sound to melow!!! It has V-force mufflers now, and they sounded really good with the small block.