I am almost ready to tackle building a tubular exhaust manifold. My initial thoughts are a true tube style exhaust manifold, that is shaped very close to stock, but with angled primaries going into the log, and a stepped log. I would also eventually like to try a shorty header (non log) with full primaries and an altered collector.

For now, my focus is log, tubular manifold.

My question is:
What size would you recommend for the primary tubing coming off the exhaust ports?
I am leaning towards 1.5 primaries, but the sizes I have to work with are:
1.25
1.5
1.65

In my head, 1.5 primaries on all cylinders, cylinders 1 and 6 carry the 1.5 to the log, step to 1.75 after cylinders 2 and 5, and 2" after 3 and 4, with a two into one 2.5 or 2.25 collector.

Suggestions on primary tubing size? Anyone know what the available full length headers out there use as primary tubing diameter?

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1976 Dart Lite /6 3 Speed

Sounds interesting, why not give it a try.....I have seen 1.5" and 1 5/8" primaries on long tube headers.

When my wife and I were at the Chrysler Corporate Center engine lab the engineers told us that they had tested various length primaries on the SL6 and suggested for the best results that we use 36" to 42" primaries for the most low end torque with a 2.5" collector 12" long. That is for racing or as a daily driver. The long tube headers like Hookers with the Super Six conversion mileage and power gains were the most significant, well over 30 mpg, corporate would not let them market the combination for fear that they wouldn't sell the 318's. Too bad the combination wasn't marketed, but that doesn't stop us from trying it.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Too bad the Clifford shorties that fit the early A-bodies are are only 18"

If one were to use the long tube headers with the Super Six, what would be the best solution to heating the manifold?

Please don't accuse me of hi-jacking a thread.

Ray

The Clifford shorties aren't as bad as you think.

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Official Cookie and Mater Tormentor.

Hot water on the bottom of the manifold. Good examples are wjajr's setup and what they use on the new Aussie manifolds.

The long length provides allot of torque at low rpm. The dyno tests they did showed a huge improvement in output at 2000-2500 rpm.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG