syn, or regular doesn't matter, its mostly operator's choice when it comes to that, as for the amount, most engines take 5 quarts of oil during an oil change. That means after you put the 5 quarts in, close it up, start the engine let it run for a minute at least to cycle the new oil into it, then shut it down, and check your dipstick. it should be close to being right, if not on the money 9 times out of 10.
