Ram Horns and dual 2.5" exhaust - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69SCSS · 02-02-2015, 08:22 PM

Hey guys, I'm tired of listening to my cheap headers make what sounds like an exhaust leak noise under my truck, and it's driving me NUTS!!! I have a full 2.5" exhaust on my truck, and wondering if a set of stock ramhorns would be too small. The collectors are 2.5", right? Just concerned that the 2.5" pipes are too much behind the manifolds. I know there's a big debate about backpressure levels (negative or positive), I'm more concerned about sound and efficiency.
I'm guessing it'll work just fine. Any thoughts appreciated.
Thanks!
Al

**Already Gone** · 02-02-2015, 08:26 PM

subscribed

Mike C · 02-02-2015, 09:04 PM

Bunch of threads on the 2 1/2" manifolds. I went from headers and 2 1/4" exhaust to manifolds and 2 1/2" exhaust. Running Dynomax Hemi Turbo mufflers (20" case). One of the best mods ever on my Jimmy.

As soon as I get a chance to put some pipe in the crossmember on my shortbed for exhaust clearance I'm going 'Vette rams horns on it with some Magnaflow mufflers I got off a parts truck I had.

You will have no issues ditching the headers IMO. I think I actually gained some low speed torque with my swap. And I got rid of the hassles of headers. No complaints.

69SCSS · 02-02-2015, 09:09 PM

Unfortunately the search function is still down, so finding those threads is tough right now.
Good to hear someone else has done it and it works out. Kinda figured, but wanted to get some opinions first.

Mike C · 02-02-2015, 09:29 PM

I think you'll be happy. I know I was enough where I'm going to do it again!

If you type "corvette rams horns" in the bar for what passes for a search box and radio button the 67-72chevytrucks.com button it comes up with loads of threads from the site.

**D.PASSMORE** · 02-02-2015, 10:46 PM

I only run 2.5 straight dump ram horns on my trucks - 4x4. Over the years I have picked up sets that were designed for Corvettes, modify them a little. The only issue is ensuring that you use the correct ex. manifold gasket or they will start leaking after a few thousand miles. If you go that route, measure the port size of the heads and port size of the manifolds, then look on Summit for the best match.

**special-K** · 02-02-2015, 11:10 PM

The truck manifolds aren't 2.5", but no problem going with 2.5" exhaust

69SCSS · 02-02-2015, 11:17 PM

Quote:

Originally Posted by special-K

The truck manifolds aren't 2.5", but no problem going with 2.5" exhaust

Are they 2.25" or 2.75"? The big block ones were 2.5" if I remember right.

SierraMtns · 02-02-2015, 11:47 PM

Quote:

Originally Posted by 69SCSS

Are they 2.25" or 2.75"? The big block ones were 2.5" if I remember right.

I believe the stock OEM truck ones are 1.9".

**D.PASSMORE** · 02-03-2015, 12:11 AM

Here is an example:
http://www.ebay.com/itm/64-65-Corvet...8b66eb&vxp=mtr

I trim off the alternator mounting flange. After that - in appearance they look identical to stock 67-72 OE straight dump truck manifolds. Again with the exception of the diameter of the exhaust pipe mounting flange.
I run 2.5 pipes from the collectors to the tips - no issues.

leftybass209 · 02-03-2015, 12:22 AM

The corvette 2.5's will work regardless of engine position you just need a competent exhaust guy to route the pipes. The style muffler you choose will effect the back pressure, but I think just about any mild+ Chevrolet v8 can handle 2.5 exhaust with no issues.

02-02-2015, 08:22 PM	#1
69SCSS Registered User Join Date: Aug 2012 Location: Neskowin OR Posts: 1,153	Ram Horns and dual 2.5" exhaust Hey guys, I'm tired of listening to my cheap headers make what sounds like an exhaust leak noise under my truck, and it's driving me NUTS!!! I have a full 2.5" exhaust on my truck, and wondering if a set of stock ramhorns would be too small. The collectors are 2.5", right? Just concerned that the 2.5" pipes are too much behind the manifolds. I know there's a big debate about backpressure levels (negative or positive), I'm more concerned about sound and efficiency. I'm guessing it'll work just fine. Any thoughts appreciated. Thanks! Al __________________ My 68 SWB Al Silveira Music <- My daughter loves this guy 8-)

02-02-2015, 08:26 PM	#2
Already Gone 70+ ( Old Skool Club ) Join Date: Nov 2003 Location: Saskatoon, Saskatchewan ,Canada Posts: 9,146	Re: Ram Horns and dual 2.5" exhaust subscribed __________________ 1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021

02-02-2015, 09:04 PM	#3
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	Re: Ram Horns and dual 2.5" exhaust Bunch of threads on the 2 1/2" manifolds. I went from headers and 2 1/4" exhaust to manifolds and 2 1/2" exhaust. Running Dynomax Hemi Turbo mufflers (20" case). One of the best mods ever on my Jimmy. As soon as I get a chance to put some pipe in the crossmember on my shortbed for exhaust clearance I'm going 'Vette rams horns on it with some Magnaflow mufflers I got off a parts truck I had. You will have no issues ditching the headers IMO. I think I actually gained some low speed torque with my swap. And I got rid of the hassles of headers. No complaints. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

02-02-2015, 09:09 PM	#4
69SCSS Registered User Join Date: Aug 2012 Location: Neskowin OR Posts: 1,153	Re: Ram Horns and dual 2.5" exhaust Unfortunately the search function is still down, so finding those threads is tough right now. Good to hear someone else has done it and it works out. Kinda figured, but wanted to get some opinions first. __________________ My 68 SWB Al Silveira Music <- My daughter loves this guy 8-)

02-02-2015, 09:29 PM	#5
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	Re: Ram Horns and dual 2.5" exhaust I think you'll be happy. I know I was enough where I'm going to do it again! If you type "corvette rams horns" in the bar for what passes for a search box and radio button the 67-72chevytrucks.com button it comes up with loads of threads from the site. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

02-02-2015, 10:46 PM	#6
D.PASSMORE One of the First Join Date: Jan 2000 Location: St. Augustine,FL. Posts: 4,059	Re: Ram Horns and dual 2.5" exhaust I only run 2.5 straight dump ram horns on my trucks - 4x4. Over the years I have picked up sets that were designed for Corvettes, modify them a little. The only issue is ensuring that you use the correct ex. manifold gasket or they will start leaking after a few thousand miles. If you go that route, measure the port size of the heads and port size of the manifolds, then look on Summit for the best match. __________________ DAVID PASSMORE ST AUGUSTINE ,FL ZIP 32084 '71 SWB K/10 CUSTOM DELUXE (Chili) '72 BLAZER K/5 Muscle Truck (Mule) '72 LWB K/20 CHEYENNE (Blackie)

02-02-2015, 11:10 PM	#7
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Ram Horns and dual 2.5" exhaust The truck manifolds aren't 2.5", but no problem going with 2.5" exhaust __________________ "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 ~

02-03-2015, 12:11 AM	#10
D.PASSMORE One of the First Join Date: Jan 2000 Location: St. Augustine,FL. Posts: 4,059	Re: Ram Horns and dual 2.5" exhaust Here is an example: http://www.ebay.com/itm/64-65-Corvet...8b66eb&vxp=mtr I trim off the alternator mounting flange. After that - in appearance they look identical to stock 67-72 OE straight dump truck manifolds. Again with the exception of the diameter of the exhaust pipe mounting flange. I run 2.5 pipes from the collectors to the tips - no issues. __________________ DAVID PASSMORE ST AUGUSTINE ,FL ZIP 32084 '71 SWB K/10 CUSTOM DELUXE (Chili) '72 BLAZER K/5 Muscle Truck (Mule) '72 LWB K/20 CHEYENNE (Blackie)

02-03-2015, 12:22 AM	#11
leftybass209 Registered User Join Date: Feb 2011 Location: Modesto, CA Posts: 2,189	Re: Ram Horns and dual 2.5" exhaust The corvette 2.5's will work regardless of engine position you just need a competent exhaust guy to route the pipes. The style muffler you choose will effect the back pressure, but I think just about any mild+ Chevrolet v8 can handle 2.5 exhaust with no issues.



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