All Small Six Intake manifold on a cross flow head

[Kevin Baker]

I was wondering what other people have done about the terrible design of the intake manifold. Even if you put a better head on an intake manifold with three different length runners is not optimal at all!
I think the best way (maybe for racing) would be to have short 2”” aluminum intakes a EFI for every cylinder like a motorcycle engine. That’s more than I want to do though.
That would be cool looking but I use thinking of having three two into one intakes. I’m sure someone else has done this.
If so what EFI or carbs. Is there or has there been anyone that made a tri-power setup for these?

 

[aussie7mains]

I was wondering what other people have done about the terrible design of the intake manifold. Even if you put a better head on an intake manifold with three different length runners is not optimal at all!
I think the best way (maybe for racing) would be to have short 2”” aluminum intakes a EFI for every cylinder like a motorcycle engine. That’s more than I want to do though.
That would be cool looking but I use thinking of having three two into one intakes. I’m sure someone else has done this.
If so what EFI or carbs. Is there or has there been anyone that made a tri-power setup for these?

There is a lot here, can i suggest you do some reading on the subject, tonnes has been written on this and other important items of the engine. the factorys has made good intakes for their chosen application, other applications need a different design. A Graham Bell has done considerable work on this and has written what i consider excellent works. What you have described as very short stubs is probably not a good design, something longer would be better. Also check what BM and Mercedes do, they are very good at this.

 

[Kevin Baker]

Where can I find these articles you’ve mentioned?

 

[rocklord]

I read about someone in Australia retrofitting a broad band manifold (BBM) from the SOHC 4.0L inline six to a Crossflow.
The BBM has butterfly valves that changes from six long runners to six short runners around 3800rpm.

 

[Kevin Baker]

I’m really leaning towards a tri-power set up. It will be easier and at the runners will be the same length.

 

[aussie7mains]

Where can I find these articles you’ve mentioned?

There books by A Graham bell, https://www.amazon.com.au/Four-Stroke-Performance-Tuning-Graham-Bell/dp/178521859X
And, https://www.amazon.com.au/Forced-Induction-Performance-Tuning-Graham/dp/1859606911
I have both and others, Phil Irving is also another author on the subject, his stuff is a little hard to find;- "Tuning for speed"

 

[aussie7mains]

I read about someone in Australia retrofitting a broad band manifold (BBM) from the SOHC 4.0L inline six to a Crossflow.
The BBM has butterfly valves that changes from six long runners to six short runners around 3800rpm.

Correct, it doesnt fit in pre 65 falcons. I would suggest if you really want one, get the whole SOHC engine, its better anyway. Aussiespeed make good manifolds for the crossflow, and a really good one is "ultraflow, limited sprint" made for two barrel carbs. the factory weber manifold is better than you think.