Everyone is always trying to squeeze the last bit of power out of their combo. This thought popped into my head last night and I want to get some opinions, and also hoping that someone has some hard data to offer here.

My block is decked .020, my heads are milled about .015. I assembled the engine at the machine shop (under the watchful eyes of the guys at Revolutionary Performance and Machine). I took the assembly home to finish mounting the accessories, exhaust and intake manifold.

Since I was already at home bolting the manifold one I really wasn't able to address the problem I had- the intake manifold would not bolt on to the heads. I had to elongate the intake manifold bolt holes some on each side in order to get the bolts on.

Now, it seems to me that most of the air charge through the intake runners in the head is going to be closer to the port roof than the port floor (?) Now, since my intake manifold has not been milled to match the heads, obviously my intake runners in the manifold are higher than the runners in the heads, creating a "step" that the air charge has to go past.

I'm not really sure how pronounced this "step" is. Just wondering if my theory is correct on this, and how much power I might be leaving on the table with my car setup the way it sits.

If this needs to be corrected I'll just pull the intake and bore it out for a 58mm throttle body at the same time the milling is done.

Thoughts?

 

Well, since nobody knows anything about this, or has any type of experience with this sort of thing I guess I will have to just try and it break new ground

 

So basically you mean the port holes do not line up perfectly? You are probably losing some power, but not a whole lot. If you had ported heads or something I can see it maybe creating a problem with the turbulance in the head, but nothing that I would think be a power robber.

 

Maybe Lloyd Elliot will comment on this.