Indeed you do. Both my cranks are ground 10 under both mains and rods; bearings need to reflect that.
So you're using a cast crank, then? Do you know if it's the standard cast or the shot-peened version?
From what I’ve read, the stock cast crank is suitable for builds up to 600hp. I only have a picture of it, tightly wrapped up in plastic with a 10/10 360 written on it... It’s from block 4006830-360-2 from late 1975 though.