Identifing 70 disc brake conversion

[Bonertee]

I have looked over numerous post. May have overlooked it somewhere. Is there any way to identify what front disc conversion has been done on my truck. It's a 70 Chevy that already had the swap done but I'm not sure what year I need to get drop spindles for. It has rubber bushings on the control arms. 1 1/4 thick rotors. I've done gotten myself confused by looking and reading over and over. Any help would be greatly appreciated. Thanks in advance.