Sanding cartridge rolls and a stone but they were old ,I need to buy some more.

The exhaust guides can rot and leak. Do yourself a favor and have a good reputable macine shop give the heads a once over. I would think reversion would have caused rust in all ports

I think water has been sitting in the manifold just under the riser on both heads.That is really my main concern because the end of the guide is a little rough around the outside.I would hate to have to buy new heads because this engine ran so so good up until last weekend,the first time I took it out in the new boat.

I ported some cast iron heads that were pretty bad and after a clean-up in a hot tank and some work with a carbide bit, cartridge rolls and then polishing they looked brand new. Maybe check the guides for runout and replace if needed........ To pay to have this work done gets pricey and kind of makes a case for just buying some new heads? TBF