Then do a what I call a running stall test. Get the car warmed up good. Pull it out in the street. When there's no traffic of course. Get hard on the brake with your left foot. Now with the right, stab the gas to the floor while delaying VERY slightly letting your foot off the brake. You want to hold it back JUST enough to allow the converter to spin up some. You're not testing for stall speed here. You're testing for "happy factor". It SHOULD pretty much liquify the rear tires if everything's a good match. If it does, I wouldn't change anything.