Inliners International Forums General Discussion Hi Performance Dual port manifold

A theoretical question....I've been wondering....always a scary thing. On V8s, Edlebrock, for instance, makes dual plane Performers and single plane Victors manifolds. The dual plane has much better off idle and street performance, while the single plane Victors and others are higher RPM manifolds.

My Clifford is single plane with big honking runners that don't promote high mixture velocity. I was looking through the Santucci book at all the old manifolds and they all appear to be single plane.

I don't plan on doing this but WHAT IF, someone were to do something like this:



The black lines is a cutaway of the standard Clifford manifold. My Edelbrock sits sideways anyway, that is the secondary is parallel to the crankshaft. Actually it's closer to the engine rather than as shown but the principal is the same.

The red line would be a piece of aluminum... say 1/4" flatbar that is welded in the middle of the bore as shown. It wouldn't have to be welded full length to be effective. Given the firing order, I'd THINK this would isolate each cylinder from the others, increase mixture velocity, and add more low end torque. Of course, if you've removed the stock boss this wouldn't accomplish anything.

Any merit to my thinking????

when that was done many years ago the boss was removed and a divider was installed into the ports.There was also a
differnt plate installed under the carb which to was divided.
Which the boss in the head it dosen't really divid anything,
Because the air just goes around it in the first place.

I did a simular modification to my Clifford & it did help the low end & mid range w/out removing any top end power.

MBHD

Take a look at the offenhauser DP for ford 240/300 I6 engines, may be interesting for you to see whats been done for other engines.

Some years ago, I saw a magazine article about somebody who did exactly what you're describing, Kerry. They took a Clifford manifold, sectioned it lengthwise through the middle, making a top and bottom half, then took 3/32 or 1/8th aluminum and formed dividers just like in your diagram, then welded the dividers in place and the manifold halves back together, and it worked much better. I'm a little surprised that Clifford never tried casting a divider into the manifold as a street option, but maybe that's too expensive or too difficult to do for the volume that they sell. Who knows?