
Here is something that I find hard to understand, but maybe it is just me. Since the manufacturers of intake manifold gaskets are able to get a pretty good fit (maybe +/- 1 mm) I would think that the ports in the cylinder heads are pretty accurately made too, ie. the heads are all alike apart from maybe +/- 1 mm. Why are the manufacurers of inlet manifolds not able to match that accuracy? That is also one of the quality issues with the Allison manifold that I have.
Fair enough if the installer had to machine off half a mm in order to get a perfect and smooth fit. But 3 mm, that is sloppy if you ask me.
Or am I being unreasonable here?