Direct Connection ( Mullen LA ) heads

K.O. SWINGER said

So if I miss something here tell me what post that I can find it, my question is why so much lift on a style of head that typically begins to stall around 550 or so, I realize it will get to maximum flow quicker but it seems extreme to me. It seems like an extreme amount of spring pressure to accommodate questionable gain?

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I’ve answered this before but I’ll do it again. You can make almost any port back up on a flow bench. Especially with the intake manifold not on the head when it’s flowed.

So let’s say at .450 lift you are flowing...I’ll pull a number out of my hat...220 CFM and at .500 you are flowing 205 and it stays there. If we assume that the port is actually backing up while it’s running with the intake manifold on, if you lift average you’ll see that more lift still gives a higher average. And that matters.

Like compression ratio, most guys don’t use enough lift. Just because a head does something at a certain lift at a certain test pressure doesn’t mean it actually does that when it’s running.