i gotta 91 camaro with a stock 305 in it i cant get a title for it so im going to part it out im going to keep the engine and trans but it hasnt been ran for a couple of years the engine is gunked up a little but still turn easy with a wrench on the crank shaft pulley should i drain all the oil out of it clean the engine and rebuild it or will it be ok to get the engine running with fresh oil will it clean itself and "ungunk" ?