Big block headers.
Thread Starter
Cruising
Joined: Nov 2009
Posts: 10
Likes: 0
Big block headers.
I have a built 454 with Brodix aluminum heads,big rectangular ports.I'm running thru stock manifolds ,I have an xpipe and 2-1/2 magnaflow mufflers.I'm running a Holly 750 HP carb thru a factory ls-6 intake (low Rise).I wonder how much power I'll realize if I put Hooker super-comp headers on this combo?I realize the rectanguar 71 exaust tips are bottle neck as is the low profile intake,anybody try this?Thanks
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Yes...DEFINITELY change to headers....you are leaving 30-50hp or more on the table depending on the engine build. There are two sets of Hooker SCs. One is 1 7/8"x3" and the other is 2 1/8"x3.5". Unless you are running 496" or larger, stick with the 1 7/8"x3"s. Try to keep the rest of the system as smooth as possible, preferably mandrel bent. You can mod the 71 squar tips for 3" openings. The rear of the tip is cut off and a 3" section of pipe must be ovaled. Cut the rear of the square out to fit the ovaled pipe. Then tig it all together on the car.
I run 3" mandrel bent, x pipe and aerochamber muffs with modded stock tips. It's worth the effort if you are trying to maximize your power to the wheels.
I run 3" mandrel bent, x pipe and aerochamber muffs with modded stock tips. It's worth the effort if you are trying to maximize your power to the wheels.
Race Director
Joined: Dec 1999
Posts: 11,094
Likes: 990
From: Sierra Foothills CA
Yes...DEFINITELY change to headers....you are leaving 30-50hp or more on the table depending on the engine build. There are two sets of Hooker SCs. One is 1 7/8"x3" and the other is 2 1/8"x3.5". Unless you are running 496" or larger, stick with the 1 7/8"x3"s. Try to keep the rest of the system as smooth as possible, preferably mandrel bent. You can mod the 71 squar tips for 3" openings. The rear of the tip is cut off and a 3" section of pipe must be ovaled. Cut the rear of the square out to fit the ovaled pipe. Then tig it all together on the car.
I run 3" mandrel bent, x pipe and aerochamber muffs with modded stock tips. It's worth the effort if you are trying to maximize your power to the wheels.
I run 3" mandrel bent, x pipe and aerochamber muffs with modded stock tips. It's worth the effort if you are trying to maximize your power to the wheels.
Since you spent the $$$ to get good heads that flow well it would be silly to lose that much power by restricting the exhaust flow. You'll definitely feel the difference. 
Melting Slicks
Joined: May 2000
Posts: 2,029
Likes: 63
Good exhaust is never waste. The original system is only 2". Much to improve there.
This one has long headers, 2.5" mandrell bent dual pipes, 2.5" in/out Afterburners and stainless original looking tips with maching 2.5" intakes:
You can buy stainless aftermarket tips ($50). Cut off the 2" pipe, enlarge the hole and replace with 2.5" or 3" pipe per your need.
This one has long headers, 2.5" mandrell bent dual pipes, 2.5" in/out Afterburners and stainless original looking tips with maching 2.5" intakes:
You can buy stainless aftermarket tips ($50). Cut off the 2" pipe, enlarge the hole and replace with 2.5" or 3" pipe per your need.
Last edited by ToniH; Mar 4, 2011 at 10:35 AM.
Burning Brakes
Joined: Oct 2002
Posts: 914
Likes: 14
From: Aberdeen, Scotland
ajrothm, That exhaust looks the business! When I get back to Houston late n the year I need to check that out. I am running MacJacks shorties with a chambered exhaust. On the engine dyno my 489 dynoed at 511 with long tube headers vs the shorties at 496hp. That might give you an idea Pwain.
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