Seems like is a hot topic lately so I hope this helps. I'm working with Chevy parts cataloges, covering '80-'88 (O ring type) since it will cover the MC SS where alot of the 800 boxes are sourced from. The base 800 p/n is 7848137, used in A (all '80-'82), B ('80-'90), G ('82-'88), list pitman arm 7837648 to be used when replacing a 605 box The sport 800 p/n is 7843135, used in G ('83-'88) (MC SS YG5, Z65) This is an odd listed 800, p/n 7848138, GZ (2.3D)(exc sport pkg Z65) (Saw in a Buick catalog w/H.D. suspension.) There is a B 800 box p/n 7833133 ('82-'84 9C1, '86-'90 7B3), unknown ratio This is the pump listed for SBC V6/V8 p/n 7839787, used in G ('82-'88, all), B ('82-'88, all) The earlier pump used is p/n 7833224 used A ('80-'81, all), B ('80-'81,w/ A/C) I have not come across any different p/n for pumps regarding RPO's for sport, heavy duty, or standard suspension or steering performance.