For what it's worth... My brother-in-law bought a 351W/C6 out of a E-150 to put in his '82 F-100 that had a 300I6/4spd. I removed the heads, rented a valve spring compressor tool from O'Reilly's and took the heads apart. No burnt valves, but the stems of the intakes had a strange rock formation growing on them (lol!). But first, right after they were taken off, I used my 4" grinder and a knotted wire cup brush to clean the chambers up and the tops of the valves. After disassembly, I sprayed the ports with carb cleaner and brake cleaner and used old tooth brushes and small wire brushes to clean the ports out. Soaked the valves, springs, retainers, keepers, and lash caps in an old antifreeze jug with the side cut out (make great bolt bins too). I used gas (yes I know, wrong thing to use) outside on the driveway. (I've since bought a 40 gal parts washer that has 20 gallons of solvent in it). I bought a hand lapping kit and hand lapped the valves. Honed the cylinders and then bottle brush finished them (actually, my dad did this part as he had rebuilt several Chrysler engines we used in the oil field for water pumps and they were his hones and big azz drill, he also brought his ring filer and filed the rings, ain't dads great?), cleaned the pistons up (use a broken ring to clean out the ring gaps), put new bearings and gaskets in it, rebuilt the carb, and it fired right up. I built the shifter linkage for it (we swapped for a auto column, but there was no linkage) and an exhaust with glasspacks and away he went, happy about everything but the gas milage. Sold it to a high school kid who thought it sounded neat. I believe its still running around, although I'm not sure its on my budget rebuild (He had a little over $900 in the conversion including buying the running motor/tranny combo, which I think he gave $500-$600 for). This was about 7 years ago.