TOPIC:

What problems would result from cutting the valve guides off at the roof of the port? I am cleaning up the ports and wonder if there is a worthwhile gain available from doing this?

I'd say no real gain in flow but you would be reducing the contact area on the guide and that might lead to a shorter life.

There are lots of other little things you can do like port polishing that would result in improved performance.

Don't do it. Leave some ramp and guide length.

Jay

jay is right, dont do it, you stand a chance of breaking a valve, and you will not gain any flow