2X to Jay's note +: pop the rocker shafts and spark plugs (or back off your adjusters as far as possible or remove them). With all the intakes closed, fill the ports with your choice of super solvent (SuperClean, lacquer thinner, acetone, paint thinner, kerosene, etc. diesel may work too but I've never tried it). Let sit for at least 24 hours or as many days as you can stand. May need to refill some ports as the valves will leak over time. Suck out the leftover with a shop vac (careful here and don't use the vac if you're using gasoline, acetone, etc.) and crank after adding oil as Jay stated. Use very light machine oil if you can or 5w oil. Re-install with Victor Reintz or Fel-Pro street gaskets, not the Printo-O-Leaks!