Ken, you're going to completely ruin your Dremel tool about the time
you're done with two cylinders. You need air tools to effectively do
a porting job - it's just too much work for a light-duty tool like
the Dremel.
As with a carburetetted engine, I wouldn't mess with the intake tract,
except possibly to blend the final passage near the valve. Theories
differ, but I subscribe to the one that believes the surface roughness
helps atomization. Note: this is not an issue with port injection.
As to exhaust ports - get them to gleam, if you can. This is an your
opportunity to help out engine efficiency too. Also note that you do
not want to hog out the head port to manifold dimensions unless you're
running a hot cam, low-restriction exhaust, and the intake is breathing
very well. Lacking these mods, the engine will scavenge better if the
gas pulse can bounce off a little ridge at the interface. Sounds weird,
but it works. Of course, if all the dimensions are going up - bigger
valve diameter, bigger manifold (header) diameter - then making the
port bigger makes sense too.
When you're putting the exhaust manifold back together, use some of the
high-temp assembly lube. It's copper. If the auto shop doesn't know
what you're talking about, you can get it at better bicycle shops, where
it's used to prevent titanium parts from welding themselves to aluminum.
A little bit of this stuff will save you a lot on Kroil and bolt
extractors.
Jim
"There is already a ban on ALL CRIME. It is not working." - Thomas Sowell
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