Another performance mod question...exhaust
Thread Starter
Pro
Joined: Mar 2015
Posts: 681
Likes: 31
From: Nebraska
Another performance mod question...exhaust
Alright...you guys have talked me into an XE262 camshaft. Still trying to decide on heads. Fortunately I have time to think about this.
Now...I know that headers will give me more power, but I am considering staying with the cast iron manifolds. How much power is a set of headers actually worth?
I like the quiet-ness of the manifolds. I don't want to occationally re-torque header bolts and replace header gaskets. This is my reason for considering sticking with the manifolds. But if the power gain is significant then my thoughts may change.
I have heard that the manifolds flow fairly well, but what do you guys think?
Now...I know that headers will give me more power, but I am considering staying with the cast iron manifolds. How much power is a set of headers actually worth?
I like the quiet-ness of the manifolds. I don't want to occationally re-torque header bolts and replace header gaskets. This is my reason for considering sticking with the manifolds. But if the power gain is significant then my thoughts may change.
I have heard that the manifolds flow fairly well, but what do you guys think?
Last edited by COOLTED; Aug 19, 2015 at 08:14 PM.
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Is this a daily driver that rarely sees full throttle use? If you intended to drag or track race it on weekends I'd go with the headers but for daily use from point A to point B I'd keep the iron manifolds. And its not necessary to use gaskets with headers as the metal-to-metal fit is more than enough to seal them.
Le Mans Master
Joined: Mar 2001
Posts: 5,738
Likes: 644
From: Lincoln, CA
The difference was very noticeable moving the headers. Everything under the curve was much better.
If you use a quality gasket they will never need replacing. After a heat cycle they should need to be tighten a 3rd time.
If you use a quality gasket they will never need replacing. After a heat cycle they should need to be tighten a 3rd time.
Safety Car
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
Headers will improve performance across the entire rpm range .. Period .. Sealing comes down to headers that match your head's exhaust ports ( d port get d-port headers) And a good gasket .
After you run and heat cycle them re-torque them and you should be worry free from leaks and loosening bolts
After you run and heat cycle them re-torque them and you should be worry free from leaks and loosening bolts
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
Cheep headers with thin flanges will give you the problems you talked about,,, spend another $100-$200 get a good set, good bolts and studs, and a good multi layer mettle gasket. and you will never have a problem.... my set was well over $1000...... never never a leek,,, never never had to re-tighten any bolts after the first heat cycle...
headers will give you more power from idle to OMG,,,, and better gas milage... and if you want them quite,,, wrap them in header wrap...
headers will give you more power from idle to OMG,,,, and better gas milage... and if you want them quite,,, wrap them in header wrap...
Drifting
Joined: Oct 2005
Posts: 1,918
Likes: 50
From: Angier nc
Yes headers are worth more power and torque everywhere.Long tube are better than shorty.
Nothing wrong with the stock manifolds for simplicity if you aren't looking for the last 10-15 hp.Make sure you have a nice mandrel bent true dual exhaust system with free flowing mufflers at a minimum.
Nothing wrong with the stock manifolds for simplicity if you aren't looking for the last 10-15 hp.Make sure you have a nice mandrel bent true dual exhaust system with free flowing mufflers at a minimum.
Le Mans Master
Joined: Oct 2007
Posts: 7,451
Likes: 974
From: RI, Now Franklin/Nashville TN
Factory 1978 Stock L-82 4 speed rated at 220 NET HP which is about 185-190 RWHP.
Went on the dyno with no emissions, 2.5 inch duals, Monza Turbo Muffler, Shorty (NOT Long tube headers), Holley 4175 650 Q jet replacement carb, Comp cams 1.52 roller tipped (NOT full Roller Rockers)...everything internal to the L-82 100% stock AND with a weak compression #6 cylinder....233 RWHP @65,000 miles on the stock motor
Difference Stock versus Shorty headers, 2,5 inch duals, no emissions...45 RWHP!!! basically just exhaust with SHORTY's. I seriously doubt that LTH's on a stock motor versus shorty headers would add much to the equation based on my experience. Probably the biggest contributor to a stock type motor is the 2.5 inch dual exhaust in my opinion.
The more power the motor makes (more airflow) the more important LTH's become to the equation...depends on how much power you are looking to make. I am planning on LTH's for the rebuilt L-82 355 with AFR heads, Roller cam (.525 lift) and 10.2:1 compression...it currently still has the shorty's and pulls very hard on hard acceleration to 6,000 RPM but do think LTH's in this application will yield several more HP.
Went on the dyno with no emissions, 2.5 inch duals, Monza Turbo Muffler, Shorty (NOT Long tube headers), Holley 4175 650 Q jet replacement carb, Comp cams 1.52 roller tipped (NOT full Roller Rockers)...everything internal to the L-82 100% stock AND with a weak compression #6 cylinder....233 RWHP @65,000 miles on the stock motor
Difference Stock versus Shorty headers, 2,5 inch duals, no emissions...45 RWHP!!! basically just exhaust with SHORTY's. I seriously doubt that LTH's on a stock motor versus shorty headers would add much to the equation based on my experience. Probably the biggest contributor to a stock type motor is the 2.5 inch dual exhaust in my opinion.
The more power the motor makes (more airflow) the more important LTH's become to the equation...depends on how much power you are looking to make. I am planning on LTH's for the rebuilt L-82 355 with AFR heads, Roller cam (.525 lift) and 10.2:1 compression...it currently still has the shorty's and pulls very hard on hard acceleration to 6,000 RPM but do think LTH's in this application will yield several more HP.
Last edited by jb78L-82; Aug 21, 2015 at 06:31 AM.
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Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Putting a cam in and not running headers is somewhat counterproductive....the headers, cam, intake all compliment each other.
I would definitely run the headers.....either Hedman or Hooker.....
Spend $400 on a set and they will treat you right.
I would also think about going to a 268 Comp.......just my opinion.
Jebby
I would definitely run the headers.....either Hedman or Hooker.....
Spend $400 on a set and they will treat you right.
I would also think about going to a 268 Comp.......just my opinion.
Jebby