I have a 6th gen, F23A. I was wondering how much of a HP gain I would get from a port and polish. I was thinking of going turbo, but I'd rather do head work first. Would the valves and springs need to be upgraded?

 

maybe 15 with a proper tune. Valves, and springs can stay stock.

but while you have the head all opened up for the P&P you might as well get new valve stem seals.

 

to tell you honostly, your p&p work on your head won't do any good without upgrading your cams. power comes from your camshaft. you can upgraded valve train and ported head and match ported intake and exhaust and big t body, etc. but without camshaft being upgraded, no use. (I am not flaming you either, just don't want you to be disappointed when it is done without cams.) sorry.

 

agreed. just the p&p alone won't have purpose. upgrade your internal components first and then do p&p last. as far as the gain, it will vary from motor to motor. the real test is to get it tuned and dynoed. one motor could put out a gain of 5hp another could do 20hp. the 20 could be a well maintenanced motor where as the 5 has issues that were ignored.