Can't answer your questions for 100% sure but I believe yes to both, but the first thing to do with a powerglide attached to a inline six (or any engine) is get rid of it and replace it with a 200R4 overdrive. Going from a 2 speed to a five speed will make the old six feel much better. Then work on the rear end gear ratio.
BTW, I work for Stovebolt Engine Co.
Tom Langdon, the owner, advises people all day long to upgrade to an overdrive before doing just about anything else.
Bruce