John, did Case add power down with the 30 series? Our '63 830 had power down, worked great when turning over new ground, and it seems my '60 630 does also. With no implement on you can move the 3pt lever to the full down position and the arms don't just slowly drop,they move down.
It seems when I have the back blade on in the angled position with the right draft arm adjusted down that I can make it cut deeper when using the full down position while moving.
Jim