I am fitting twin 1.5 inch carbs to my 1360 re13 engine

I am looking at having a steel inlet manifold made.

I read some where, (which i cannot now find of course) that the balance tube is too big one a standard twin alui manifold.

Is this correct, all therorys appreciated

Ta

Kiwiinwgtn

Vizard said it was too big, so he designed a prototype manifold which could have the volume adjusted, but I digress..
The twin SU manifold with the best performance rep is the Maniflow one, it uses a much smaller balance pipe than the BMC ones.

Both ports flow intermittently, as in each there are 2 suction strokes followed by 2 pauses... so the reason for a balance pipe is to keep some manifold vacuum at the carbys, when there is no flow through the port (ie the engine is sucking on the other one). If you don't do this you can get `piston flutter' which doesn't do wonders for the a/f ratio.

But a Weber or Dellorto has no need for a balance pipe, because it is not a constant depression carby.

<edit> see this one in NZ, looks very similar to the Maniflow...
http://www.ausmini.com/forums/viewtopic.php?t=43311

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.