going from stock to vette ramhorns - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bigvinnie · 09-04-2003, 06:33 PM

Does changing to the 2.5" manifolds require a change to the head pipes and mounting flange/collar, or are the manifold studs on the vette rams the same distance apart so that I can use my existing plumbing...???

thanks.

lukecp · 09-04-2003, 07:16 PM

The vette ramshorns dump straight down....your p/u ramshorns should be angled backwards. Unless you already have 2.5" pipes, you will have to change your headpipes and proably the rest of your exhaust system anyways. 2.5" manifolds really won't give you any more power if they are going into a restrictive 2" dual exhaust system. Proably a good time to get a new free-flowing 2.5" exhaust system to match up with your headers.

bigvinnie · 09-04-2003, 07:58 PM

thanks for the reply... my current rams are the small I.D. 4X4 units that dump straight down, but upgrading the entire exhaust system to take advantage of the increased flow makes sense... I believe my current pipes are 2.25", so I'll look into a new 2.5" system. Was thinking about going to the Dynomax hemi super turbo mufflers anyway...

All it takes is money.

nu2-72 · 09-04-2003, 09:05 PM

2.5" exhaust over 2.0" = 64% increase in flow. Not too shabby.

Longhorn Man · 09-06-2003, 11:53 PM

Quote:

64% increase in flow.

In theory...but in theory, comunisim works.

If the restriction is before the larger pipe, (As in the manifold it's self) then the extra girth in pipe won't do anything at all.

And acording to what I have read on the subject, that is the case on this situation.
Again, from what I have read...expect more like 15 to 25% flow increase.

nu2-72 · 09-07-2003, 08:54 AM

09-04-2003, 06:33 PM	#1
bigvinnie Registered User Join Date: Aug 2001 Location: escondido, ca 92026 Posts: 1,222	going from stock to vette ramhorns Does changing to the 2.5" manifolds require a change to the head pipes and mounting flange/collar, or are the manifold studs on the vette rams the same distance apart so that I can use my existing plumbing...??? thanks. __________________ '72 short step, 350, 700R4, tilt, ps, pdb, a/c, lowered coils, etc., other work in progress... San Diego, CA 72 Stepside Project

09-04-2003, 07:16 PM	#2
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	The vette ramshorns dump straight down....your p/u ramshorns should be angled backwards. Unless you already have 2.5" pipes, you will have to change your headpipes and proably the rest of your exhaust system anyways. 2.5" manifolds really won't give you any more power if they are going into a restrictive 2" dual exhaust system. Proably a good time to get a new free-flowing 2.5" exhaust system to match up with your headers. __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

09-04-2003, 07:58 PM	#3
bigvinnie Registered User Join Date: Aug 2001 Location: escondido, ca 92026 Posts: 1,222	thanks for the reply... my current rams are the small I.D. 4X4 units that dump straight down, but upgrading the entire exhaust system to take advantage of the increased flow makes sense... I believe my current pipes are 2.25", so I'll look into a new 2.5" system. Was thinking about going to the Dynomax hemi super turbo mufflers anyway... All it takes is money. __________________ '72 short step, 350, 700R4, tilt, ps, pdb, a/c, lowered coils, etc., other work in progress... San Diego, CA 72 Stepside Project Last edited by bigvinnie; 09-04-2003 at 08:01 PM.

09-04-2003, 09:05 PM	#4
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	2.5" exhaust over 2.0" = 64% increase in flow. Not too shabby. __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

09-07-2003, 08:54 AM	#6
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	Read more. __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

09-08-2003, 12:12 AM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Even if what I have read is not 100% acurate, you can't deny that the major restriction ir at the top of the manifold when the gasses are moving faster, and the restrictions are greatest. I would never expect a 60% increase from anything but the best headers.

09-08-2003, 09:33 PM	#8
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	Sure I can deny that. __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.