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#1
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Exhaust manifold flange size
What the biggest size pipe that can be mounted on a stock d ports exhaust manifold flange. Looking at the ram air type manifolds. Thanks
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1970 firebird, 468, e heads, |
#2
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I have the RamAir 2.5 manifolds with these down pipes in the attachment, which allows 3 inch exhaust all the way to the tail pipes.
https://www.ramairrestoration.com/po...y-headers.html
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74 Formula 469, 6X-4's, 72 Intake, Ramair Manifolds. 3 inch exhaust with x-pipe Custom Roller Cam, 1.52 Roller Rockers Quadrajet done by Cliff 3:42 gears 12.075 @ 112.70 12.092 @ 112.43 12.128 @ 111.71 |
#3
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thanks
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1970 firebird, 468, e heads, |
#4
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With log manifolds and 2 bolt flanges 2 1/4" is usually about as big as you can go.
The RA manifolds have larger flange areas enabling 2 1/2" if you enlarge the center hole in the flange. There is a way to adapt up to 3" pipes using header collector flanges adapted to the 2 or 3 hole flanges, requires welding and fab skills. Basically the old flange pattern is used to build a plate that is first bolted to the manifold and then has the 3 hole header collector flange pattern on the 3 inch pipe that is then bolted to the adapter plate. Way back years ago, on the 67 GTO in my middle signature picture I built adapters to adapt the 3 hole Pontiac RA head pipes to driveshaft tubing (3 1/2 inch OD) that dumped at the rear axle. The seat of the pants dyno was feeling the improvement...LOL
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Brad Yost 1973 T/A (SOLD) 2005 GTO 1984 Grand Prix 100% Pontiacs in my driveway!!! What's in your driveway? If you don't take some of the RACETRACK home with you, Ya got cheated Last edited by Sirrotica; 05-30-2019 at 09:26 AM. |
#5
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I also have a complete 3" system from RamAir with X pipe and electric cut outs. Fits like a glove. Sounds GREAT..
"Bill"! |
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