As you can see, I mounted my front mounts directly to the cast in ears of the block. My center to center distance is 18", but the tubes for the bolts to go through on top of the square stock are not centered, they are shifted to the pass side of the block to the edge of the square tubing.

I built the main frame with a outside dimension of 2'x 4' . to give you some perspective. Its 1.5" x 3" tubing.

The lower bolt hole on the 833 that I showed in the pic above is approx 2.25"-2.50" below the pan rail.

If you can make the one your getting work for you, grab it if its cheap. I have around $250-300 into what you see so far, but I built it all new and from scratch. I looked at used ones and new ones and decided I liked alot of features of alot of different stands. And I decided I'd probably hack up a used one just to get itto the the point i'd like it, so i'd figure i'd just start from scratch.

But I also plan on offering this as a future service too, so I wanted it built for alot of future use, not just once or twice.