Please update your profile so we know what your working with.
Both the 30 and the 27 drop on the same side, so that is a non issue.
You can use the original column if you want. You will have to cut it outside the firewall and install a thrust washer and u joint to route the shaft to the steering box. Otherwise you there are a number of different columns that you can install.
The original Ross steering is poor at best, but if you decide to keep it, you will need to upgrade to a single tie rod and drag link, as well as rebuild both the bellcrank and box, as they are most likely worn and sloppy.
If your running the V6, there isn't a better engine to use. The 4 is a bit anemic, but is serviceable. Since the early CJ's are shorter, a V8 swap will entail cutting the grill in order to mount the radiator. If you are serious about upgrading the engine, I would suggest a Buick or Chevy V6 due to it's availability and size.
The frame will handle the load, the issue is the area around the fixed spring hangers. The C channel flexes and frame cracks in this area are common. Check yours for this issue. If it is cracked, it can be repaired by welding and fish scaling.