i have an 81gs atm with some racing beat springs and some struts as well and was wondering if they will fit on the 85 gs.

 

Yes. Strut cartridges and springs are the same from 81-85.
You can either use the entire front strut housings and rotors from the 81, or swap the cartridges into the 85 housings. Only difference between the 81 and 85 housings, is the wheel bearings. Therefore, you must use the rotors to match whichever strut housings you are using.