Another option, drain one quart of oil out, put one quart of trans fluid in. Drive it a while. Change oil. The detergent in the trans fluid can break down some of the gunk that can get caught in the check valves of the lifters.
You could eat off the inside of the engine everything is new and restored. If there is something in it it's not gunk. I also looked very carefully for metal or other foreign material when I changed the oil. It looked like new still.