Raising exhaust port , how much compression to drop ?

[phillnjack]

ok first off I am going to be raising some exhaust ports this week coming on omc oval port 56 .
Now I plan on raising the exhaust port around 40 thou as thats about as much as can be done without digging into the alloy roof of the port.
(will obviously be putting back the same chamfer angle that is on the port already )
I will also be polishing the exhaust port as far down as I can see plus a bit more with a flexible shaft type thing ( still got to make the flexi thing).
At the moment the cold cranking compression is 145-147-145...so I just call it 145psi compression.
When the ports are raised what compression can I expect it to drop too without doing anything to the head ?

i know it will not be the same compression obviously, but any idea how much it will drop to, ? 130 -135 ?
or will it drop a lot more than that.?

[phillnjack]

Nobody ?
almost a year and not one answer.. surprised at that

[baja200merk]

I doubt you will see a difference on the gauge going up .040.