Splitting the exhaust manifold

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Splitting the exhaust manifold

Post #1 by peeeot » Mon Apr 09, 2018 1:38 pm

Usually, inline six exhausts are split into two outlets with 123 and 456 grouped together. Due to the design of the stock manifold, I have been considering whether a 3-way split would be best, with 12 34 56 paired together and then brought together into a single pipe a few feet downstream. This would allow the stock manifold heat to work. Externally, only the new flanges would need to be added. Internally, two blocking plates would be added.

Any reason why this would be a bad idea? Might it have any advantage or disadvantage relative to the normal 2-way split? If it would be beneficial, what would be a good pipe diameter for the 3 initial pipes, and for the single after they join together?

Alternatively, a 4/2 split would be easily accomplished by installing just one blocking plate internally and one extra outlet. This would be simpler and cheaper, and I've heard it can sound mean, but would it carry a performance advantage?

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Re: Splitting the exhaust manifold

Post #2 by bubba22349 » Sun Apr 15, 2018 9:15 am

On the three way spilt I think at that point you would be better off getting a set of headers which would give you the best reasults. As for splitting stock 223 exhaust Manafold that was done by the old timers traditionally was different than other inline engines. This was done to give these old six'es a true duel exhaust system and they do sound mean. If I remember right it was more of like a 4 / 2 split to get the best results this is because of the unique port layouts of the 223. Good luck :thumbup: :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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