[HondaDustR]

Check the intake manifold gaskets for proper dimensions. Unfortunately, this is probably only really possible to do well if the cylinder head is dismounted and the valves removed, but if you happen to be porting a spare head anyway, might as well pick up a spare manifold to match to it.. I've seen so many gaskets that are cut a tad smaller than the actual ports, or cut off center. Why spend 20+ hrs porting and polishing if a stupid piece of paper is hanging out into the air stream? They should be flush for best results. Too large is not good either, since it creates a ridge that will probably cause slight localised turbulence, but not nearly as bad as too small. I had to trim the AFM to airbox gasket so it didn't intrude on the airflow.

What really needs to be done is the inside of the intake manifold. It looks like crap in it's stock form, but it's so enclosed, I have no idea how it could be done. Not to mention it is sooo bad, it would take forever without some kind of thing other than fingers and sandpaper. It would probably be easier to just fabricate a custom one that isn't cast using pine cones. Or retrofit the tuned manifold used in the 968 by cutting the stock one just before the fuel injectors and welding the 968 part, which would also be apropriately trimmed to fit.