I must correct myself
I had previously stated that flowing in reverse was a bad idea and it is. However, I reread the article and they are BLOWING through the manifold. This is a valid method for flowing the manifold and for equalizing the runner flow. IN THE MANIFOLD ITSELF!
This method DOES NOT account for what happens when the head and manifold are bolted together. (or the actual carb you intend to use)While you can acheive equal or greater flow from your manifold intake runners(than your head ports) you are not addressing what happens at the head. The head port AND manifold need to be ported together to insure flow is directed to where it needs to be throughout the valve lift curve. I still say drawing the flow through with suction from the chamber side of the head better resembles a running engine than blowing through an adapter on the manifold. (although a supercharged application could be different situation) In summary I feel the best result with a typical flow bench is to do what you got to do to support it but mount the head to the bench, the manifold to the head, and your carb to the manifold. You must address the entire system for BEST results, not just equalize runner flow to match head flow that was measured with a radius around the port that does not in any way resemble the manifold runner.
|