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03-24-2007, 12:33 AM
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#1 |
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Registered User
Join Date: Mar 2007
Location: Oregon
Posts: 109
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Dual Exhaust
Howdy all,
my '70 K20 has a 350 with dual exhaust. The exhaust on each side are independant and not connected together anywhere. Is it better to have a crossover pipe between them to balance the exhaust? What do you'all have? Thanks! CLT. |
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03-24-2007, 12:50 AM
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#2 |
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Senior Member
Join Date: Dec 2003
Location: Colorado
Posts: 351
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Re: Dual Exhaust
If you have a stock intake manifold, then you don't need a crossover pipe. The exhaust is equalized in the crossover on the intake. Sounds weird but that's the way they used to do it.
A crossover pipe would give you a little better performance though. I have an after market Holley intake that doesn't balance the exhaust, so I use a crossover.
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The Fastor Pastor '68 swb, 447 BBC/ 6-71 Weiand, Dual 950 Bigs Carbs/ 2 1/2" Header tubes - 4" collectors/ M-21 4speed: '70 swb; TH-400 - bagged & shaved. Looking for new engine or parts. Wife - Original {A Real Classic!} 
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03-24-2007, 12:56 AM
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#3 |
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Registered User
Join Date: Mar 2007
Location: Oregon
Posts: 109
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Re: Dual Exhaust
I forgot to mention, mine has an Edelbrock intake, so I don't know if it has a crossover built in. It does still have the cool original ram horn exhaust manifolds though!
CLT. |
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03-24-2007, 01:05 AM
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#4 |
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Registered User
Join Date: Aug 2006
Location: Bakersfield,CA
Posts: 7,893
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Re: Dual Exhaust
i have the stock intake and stock ramhorns with duals and no crossover and it runs just fine however the crossover will help with lowend torque and itll actually make it quieter to
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-steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME |
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03-24-2007, 08:12 AM
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#5 |
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Special Order
  
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,861
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Re: Dual Exhaust
I`ve never run a crossover on anything I`ve had.It`s all new to me.I never noticed any lack in performance.I think the benefits are minimal.
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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03-24-2007, 08:44 AM
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#6 |
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Senior Member
Join Date: Sep 2004
Location: Terrell, TX
Posts: 1,967
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Re: Dual Exhaust
If you do one, know that the X=pipe configuration is better than a straight crossover. Got a friend in Utah that runs one on his Elky and he swears by them.
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Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps. |
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03-24-2007, 11:20 AM
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#7 |
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Registered User
Join Date: Dec 2006
Location: Rhode Island
Posts: 602
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Re: Dual Exhaust
They generally perform better in higher RPM ranges. Performance gains in lower/stock engine RPM ranges is generally not noticeable (someone sure to argue this point) and seldom worth the cost of installing it. I agree that if you're going to put one in, you'll gain more perf from an X-pipe than an H pipe.
I have an H pipe crossover on my Elky 454 and it's fine, but for cruising I like the lower frequency "thumpier" sound better on my 454 Truck with no crossover. (Headers, Flowmasters and Edelbrock intakes on both).
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03-24-2007, 02:25 PM
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#8 | |
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Registered User
Join Date: Dec 2003
Location: here
Posts: 5,789
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Re: Dual Exhaust
Quote:
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03-25-2007, 12:06 PM
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#9 | |
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Senior Member
Join Date: Mar 2007
Location: VANCOUVER ISLAND, B.C., Canada
Posts: 1,602
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Re: Dual Exhaust
Quote:
The only car that I ever ran a cross over pipe on was an early Vette and they came from the factory that way. My understanding why G.M. did this was to equalize the amount of back pressure to give exhaust a balanced flow. This in turn would allow the engine to breath better creating hp advantages. Unlike Hot Rod applications where you find the cross over back after the headers and just before the mufflers, a Corvette crossover was installed just under the front of the oil pan close to the exhaust manifolds. esll. Picture of my Vette taken in 1972.
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Tomorrow is for doing today's stuff. ************************************* This truck has just the right amount of energy for me! Author: Warren Lake .... (member) Last edited by EAST SIDE LOW LIFE; 03-25-2007 at 12:15 PM. |
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03-25-2007, 04:25 PM
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#10 |
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Born Psycho
 
Join Date: Feb 2001
Location: brentwood,cal,usa
Posts: 4,861
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Re: Dual Exhaust
the H-pipe was used on small block fords running dual exhaust to balance out the sound, otherwise they sound like they're missing on the left side. somewhere along the line it was tested on a dyno and found to help low end torque numbers. then the X-pipe came along with the flowmaster scavenger pipes and they are supposed to work better than the standard H-pipe since they actually pull exhaust from one side to the other.
on a stock motor they don't benifit much but with engine mods they definitly help.
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jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA |
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