2drexploder,
A quality flow benched port and polish job will cost approximately $800 + parts on iron heads; though valve guides are expected, you could get lucky on the rest of it being within spec.
There is a HUGE difference between this type of quality work and the "fabled" port match hack-job. If you are considering a cam to increase performance, definitely have the heads flow bench P/P as the machinist will be able to recommend a custom cam grind that is exactly correct for YOUR engine. Even if you aren't planning a cam upgrade having your heads ported and flow matched to your intakes with make a substantial improvement in performance efficiency. Ported heads matched to intakes will also benefit from good exhaust flow (headers and improved flow exhaust).