I dont have the actual plans for this beastly thing,---but it was built by ABBOT BROS. from Blythville, ARK. and is shop made from common stock materials!
If you can work from pics I can go get some of it and post or send them and we might be able to get deminsions from it! I did make it 8 inches to fit 560 when I sold the super md that I had used it on for about 10 years!---It laughs at 2200 pound round hay bales and the big backhoe that I used to have on it!thanks: sonny