300guy

I’m in the process of rebuilding the engine from my 1994 968.

I’m considering porting and polishing the cylinder head.

To what degree are the ports usually polished? 140 grit on intake side, mirror polish on exhaust?

Is this a worthwhile activity?

Opinions and details on related experience would be much appreciated!

Thanks guys!

jgporsche

If you do anything, don't do much. The ports are already HUGE! a nice polish would be all you need.

300guy

Thanks Jesse,

anyone have information on recommended surface finish of ports? As in... mirror polish, 80 grit, 100, 140... ?

944CS

not a mirror polish on either side, 140 grit will be ok, make sure the lines from the "polish" are perpendicular to the flow of the air, this creates a barrier separation and reduces surface friction even more. Also, if you have the head off and the valves out, you may want to check and see how well the intake manifold matches up to the cylinder head ports, as this is also an area that might be improved