[Rain Man]

I've been hip to balance or H pipes since the days of the '60's Mopar muscle cars and to the best of my knowledge they were the first guys to do this on regular production cars. Mopars were boss at the drags and I learned a little from their engineering innovations but just the same I've been enamored with Chevy big blocks all my life. The H pipe actually quiets the exhaust to some degree and it does feel like it may add some power but I've never ran dyno tests. Now the new craze is the X-pipe. I did run across an article about a 2002 standard 5.7L Corvette that made progressive modifications such as mufflers, balance pipes, and finally X-pipes where they reported about 12 extra horsepower gained with the addition of the X-pipes.
I've heard pros and a few cons and I'm wondering what the Chevelle gearheads are doing for best exhaust performance.
Rain Man

 

[71malibu406]

X-pipe is what i run. the general concensus is that if you have neither an H or an X pipe then go with the X pipe. if you already have the H pipe it's probably not going to make much difference for the time/money spent.

 

[Motorhead62]

Rain Man,

I think it depends on how radical your engine is. The more power you make the more critical a good exhaust is. How much power are you making and what size is your engine?

 

[Rain Man]

I have a .060 over stock L78 396 w/ the exception of a Comp solid cam & .560 lift, and Hooker headers running through a dual exhaust and Magnaflow mufflers. No H pipe.

 

[454Malibu]

Car Craft did a test. Here's an article http://www.carcraft.com/techarticles/69238/

 

[jtm60]

that test is pretty weak.

 

[DOUG G]

that test is pretty weak.

I have to agree. Off the shelf compared to custom race set-up.

"we ran a 2-½-inch bolt-together system consisting of a BBK short off-road H-pipe designed to fit the company’s full-length headers connected to a set of race-type 2-½-inch welded mufflers with turndowns."

"the guys had built a really trick system consisting of 2-½-inch tubing from the header collectors into the X-pipe, 3-inch out of the X flaring into 3½-inch tubing running for about 26 inches before necking back down into a pair of 3-inch mufflers with turn-downs."

 

[bisjoe]

X should be better than H but either is a lot better than plain duals. I went to 2-1/4" pipes, better flowing mufflers and H and that all together made a big difference in power. No dyno but I'd guess 10hp.

 

[BillsCamino]

Two weeks ago we installed a H pipe on two different Chevelles...my bro-in-law's '69 383 and my '70 w/540.
Track time that weekend showed a pretty substantial ET improvement on the '69 (.20) but little to none (.01) on the '70 with no other changes done to either.
The '69 runs 1 5/8" primary headers, 2 1/2" full exhaust with DynoMax Ultra and full tails.
The '70 has 2 1/8" primary, 3" exhaust thru Ultra Flows and 3" dumps.
I guess basically what I'm saying is why not install a H or Y pipe...it may not help but what's it gonna hurt?