inlet manifold flowing

[Gadgetman]

Has anyone ground out or re-profiled a straight 6 inlet manifold?

looking down the carb side there is a part of the casting (marked on the picture) that could be re-profiled to get a better flow to the #2 & #5 cylinders?

 

[Clive]

I don't remember the specifics, but there is an issue with some of the 6 cylinder manifolds where each branch flows different amounts. Certainly Chris Witor site may have info.

I am pretty sure some time on google will bring up info on the best way to flow an inlet, something that is a simple way to get a more efficient engine.

[Steve P]

Gareth Thomas did extensive work on my HS6 `long tract` manifold (see avatar) when i built my 2.5,matched to the work with the head he also did, and tested all the way through on a flow bench to get the best results possible.

All i can tell you that it goes really well and has bags of torque.

Steve

[Guest]

Steve.

Interesting that you mention the "long tract" inlet manifold in relation to torque.

It was a design that the Rover P6 vehicles (not V8) used during the 60's with the SU HS8 carbs, they found that by increasing the length of the inlet tubes ever so slightly had a significant increase on torque availability. In fairness part of the reason for the long tract used by Rover, came about as a result of the superb engine design which as you probably know was specifically engineered for the P6 models.

And of course that was in standard stock let alone machining and matching !!

Regards.

Richard.