got quoted $750 for a small port (complete dressed engine though)
only prob is small ports done come up that much.
thats more than a reco' kit, but not once you take into account the time it takes to do it, which is a few days for an amateur (not including the removal and refit) plus running around getting stuff machined ect.
other thing to note is, if you replace the engine, your old one is still worth money, offsetting the replacement price even more.