David Vizard, Uncle Tony's garage, Unity motorsport. Mission impossible Dodge 302 Head porting

Just add a nice bead of clay around the hole on the manifold you’re testing.
It’ll either pick up flow or it won’t.

Click to expand...

Looks like it was worth about 14cfm

Here’s some more unsolicited commentary.....

When he was doing the development work on the head, he just used a clay radius entry, and followed the flow......without any regard for what/ how the manifold would impact the flow.
Just get the head as good as you can.

Now that he’s moved on to reworking the manifold, he’s obsessing about trying to “simulate” what’s going to happen with the carb attached.

My approach would be to do it the same way the head was done.
Use the clay radius entry, port the manifold to be as good as you can........and then “it is what it is” with the actual carb installed.
Just like the head is what it is with the manifold attached.

If I got to the point where the manifold was basically done, but the carb wasn’t ready, and I wanted to get an idea of how the carb would impact the flow........
I’d procure a stock 318 carb, knock the boosters out of it, clean up the venturi, thin out the shaft a bit, and make a nice radius entry for it out of a piece of wood.

I’d also come up with a way to get a decent, reapeatable, flow number on the carb itself.