I have a 700R4 in my 39 Pontiac. Have you wired it for the lockup? There are several ways ans a little research on web will show you how.I bought the Painless kit for mine and it works well. I get about 250-300 Rpm when it locks up.

Your shifting problems could be your TV cable adjustment. You need the carb bracket to mount the cable at the proper angle and the little arm and button for the carb linkage arm to get the correct arc and angle on the throttle. It's a bit of expense and time getting it all modified and set up but worth it in the end. Don't drive the car without the tv cable properly set up as you will destroy the trans in short order.