Pulling the engine for new freeze plugs

Use the stock rods. As said earlier the 340 rods are heavier and will cause balance problems. You have to add weight to the crank which is very expensive. Egge has HP pistons for you if you need to overbore although they will drop your compression a point which is ok with today's fuels.I don't have the specs handy but if the ridge/taper isn't too bad you can hone and re-ring. Your machine shop will know what's best. toolman