Shorty headers
Thread Starter
Instructor
Joined: Sep 2017
Posts: 207
Likes: 53
Shorty headers
Can someone tell me were to get a set of shorty headers that work with stock exhaust flange. I found a bunch that have the collectors with them but I want to use stock bolt up flange 
Burning Brakes
Joined: Oct 2012
Posts: 1,152
Likes: 252
https://www.corvetteforum.com/forums...n-an-81-a.html
Last edited by Dynra Rockets; Sep 10, 2017 at 01:34 PM.
Race Director
Joined: Mar 2017
Posts: 11,933
Likes: 4,497
From: Virginia
Would a 2.5" collector work for you, or do you need the 2"? There are a number of cheap, Chinese cast repros out there at Summit, Jegs, and elsewhere. I'll probably try a pair on my '80 at some point. I have a very short section of 2" pipe before the rest of the exhaust is 2.5" starting at the turns. I'd replace that at the same time, and have an exhaust shop do the welds. I could get O2 sensor bungs at the same time.
Burning Brakes
Joined: Oct 2012
Posts: 1,152
Likes: 252
OEM 81-82 have the tubes up high
OEM 84-91 have the tubes down low.
If you have an automatic you can use either. If you have a stock manual with Z bar then you cannot use the C4 on the drivers side as it interferes with the Z bar.
I have a 81-82 on the drivers side and a 84-91 on the passenger side. (my original plan was to use C4 but then when installing I discovered the Z-bar foul, so had to source a 81/82 for the drivers side)
I personally would not recommend going the OEM route unless you already have some laying around and do not need more than 300 hp. Aftermarket headers are far superior and do not require any reconditioning such as tube spreading, welding the AIR holes shut or rust removal.
Last edited by Dynra Rockets; Sep 10, 2017 at 05:21 PM.
Le Mans Master
Joined: Jul 2000
Posts: 6,664
Likes: 162
From: columbia city in
I have less than 300 hp . I have the automatic .yes I could go aftermarket but I don't want to change the exhaust pipes.If I take out the tubes inside the factory headers close up the holes ,they would be better than what I have.the info that you have told me is helpful thankyou.
Burning Brakes
Joined: Oct 2012
Posts: 1,152
Likes: 252
Reducer:
flare donut built in:
Last edited by Dynra Rockets; Sep 10, 2017 at 06:33 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Le Mans Master
Joined: Oct 2007
Posts: 7,445
Likes: 971
From: Tennessee/Rhode Island
Speedway has what you want in a 2.5 inch ram horn that will fit a stock exhaust system:
http://www.speedwaymotors.com/Corvet...fold,9133.html
I would not bother with McJacks or the 81-82 tubular manifolds, not worth the effort for the return in power. I had McJacks for 10 years and yes better than the 2 inch ram horn but I wonder about the 2.5 inch ramhorns???????????....
http://www.speedwaymotors.com/Corvet...fold,9133.html
I would not bother with McJacks or the 81-82 tubular manifolds, not worth the effort for the return in power. I had McJacks for 10 years and yes better than the 2 inch ram horn but I wonder about the 2.5 inch ramhorns???????????....
Last edited by jb78L-82; Sep 10, 2017 at 06:40 PM.
Burning Brakes
Joined: Oct 2012
Posts: 1,152
Likes: 252
The only thing that is different for mounting is the length of the bolts. If possible try to source a set with bolts included. Also note that the 87.5-91 C4 are raised D port style, they will work fine though.
Intermediate
Joined: Nov 2006
Posts: 44
Likes: 0
Ramhorn 2.5"
Speedway has what you want in a 2.5 inch ram horn that will fit a stock exhaust system:
http://www.speedwaymotors.com/Corvet...fold,9133.html
I would not bother with McJacks or the 81-82 tubular manifolds, not worth the effort for the return in power. I had McJacks for 10 years and yes better than the 2 inch ram horn but I wonder about the 2.5 inch ramhorns???????????....
http://www.speedwaymotors.com/Corvet...fold,9133.html
I would not bother with McJacks or the 81-82 tubular manifolds, not worth the effort for the return in power. I had McJacks for 10 years and yes better than the 2 inch ram horn but I wonder about the 2.5 inch ramhorns???????????....
Advantage will be less heat and much easier to port the ramhorn. You can shape the ports because there is more material to work with.
Just my 2 cents
Burning Brakes
Joined: Oct 2002
Posts: 914
Likes: 14
From: Aberdeen, Scotland
I have MacJacks on my BB. They offer awesome quality and they fit! As for the no performance gain I call BS. My BB with long tube 4-1s dyno'ed at 511hp. With MacJacks she only lost 15hp and pulled 496hp! I did not perform a pull through the cast iron manifolds, but I highly doubt they would put out the same.
Thread Starter
Instructor
Joined: Sep 2017
Posts: 207
Likes: 53
Those all have flat flanges that require some sort of "reducer" adapter to connect to the exhaust. Sounds like these guys are looking for a manifold that has the flare donut built in so they can use their existing stock exhaust as-is without cutting or welding.
Reducer:
flare donut built in:
Reducer:
flare donut built in:
Le Mans Master
Joined: Oct 2007
Posts: 7,445
Likes: 971
From: Tennessee/Rhode Island
I have MacJacks on my BB. They offer awesome quality and they fit! As for the no performance gain I call BS. My BB with long tube 4-1s dyno'ed at 511hp. With MacJacks she only lost 15hp and pulled 496hp! I did not perform a pull through the cast iron manifolds, but I highly doubt they would put out the same.
I used my McJacks on the rebuilt/upgraded (2014) 355 L-82 (450 Gross HP with Roller cam and AFR heads)) up to this year and the McJacks were great but I switched this year to 1 7/8 inch LTH and the difference is noticeable in the 3,500-6,000 RPM range with the LTH...you can feel the engine pull harder than with the 1 5/8 inch Shorty McJacks.....
Last edited by jb78L-82; Sep 11, 2017 at 06:04 AM.
Burning Brakes
Joined: Oct 2012
Posts: 1,152
Likes: 252
The bottom pic is the OEM C4 manifolds cermaic coated by McJacks.
These are the McJacks manifolds referenced above:
http://www.vetteheaders.com/c3-corvette-headers/
R
These are the McJacks manifolds referenced above:
http://www.vetteheaders.com/c3-corvette-headers/
R
Last edited by Dynra Rockets; Sep 11, 2017 at 06:32 AM.
Intermediate
Joined: Nov 2006
Posts: 44
Likes: 0
Tidbit
I spoke with a rep from mcjacks a few years ago. They buy old oem exhausts and clean them up. They clean up welds and imperfections then ceramic coat them. Very nice work. Interesting point, they claim these are not smog legal in CA. However I found out that since they have the original one part number, these are considered oem and therefore are legal in CA.
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Hedman has a series of long tube headers that are CA legal - with and without AIR tubes. AIR tubes are only required for cars that came with them originally (typically CA L48, L82 and I *think* high altitude cars but am not sure on that one).
You'll need to do a little bit of welding work to fit the exhaust up to the stock system, but it's definitely an option if long tubes are on your list.
You'll need to do a little bit of welding work to fit the exhaust up to the stock system, but it's definitely an option if long tubes are on your list.
Last edited by Shark Racer; Sep 11, 2017 at 06:09 PM.
