Whiplash Servo?
I used the sullivan stainless steel horns & 1 1/2" airwild servo arms on hitec 5945 digitals, work great. I used great planes swivel ball links 4-40, the 4-40 bolts do not fit the sullivan horns & it is just about impossible to drill them but I have a hole punch tool made for punching stainless so I punched the holes on the horns to 4-40, worked good. The sullivan horns I used are 1 1/8".
Gil