Dimensions for lift arm are described as if it was on a grid:
1st hole 7/8"dia x0, y0 2nd hole 7/8"dia x7-1/4" , y2-1/4" 3rd hole 7/8"dia x10-5/8" ,y1-3/4" 4th hole 1-1/8"dia x20-5/8" , y0
Material is 7/16" plate steel
Hope this helps