Which power steering box do I need to use???

[71elect]

I'm trying to convert my 71' GMC 1/2 ton 2wd from manual steering to power steering. I do have access to a 1974 chevy 2wd 3/4 ton power steering gearbox. Can I use the 3/4 ton gear box or will it be to big for the 1/2 ton application( as far as mating up to everything)? The 3/4 ton pitman arm looks to have more of a bend in it than the 1/2 ton, is this swap-able between units? Or should I just look for a 1/2 ton 2wd gearbox instead? Any help is appreciated!!

[68 Suburban]

That should work fine. There is no difference between the 1/2 and 3/4 gear boxes. I put a 76 Box on my 68 burb. I did have to get a 76 pitman arm because it has the bigger shaft hole for the gear box. It was only $20 at autozone.

[71elect]

68 Suburban,
Thanks!! Glad to know that the 3/4 and 1/2 ton boxes are the same. I do have the original pitman arm still attached to the 3/4 ton gearbox. I'll see if I can pick up a 1/2 ton power gearbox pitman arm to fit my application.

[68 Suburban]

I think the pitman arms should be the same? If you have the pitman arm with the box, you should be good to go. I think the only place the arm is different is on the box side, and not the drag link side.

[SEVEND2]

hmm I changed my 72 from manual to power steering:
had to change the gear box, pitman arm, steering coupler connecting the shaft to the box, water pump to a long pump, change pullies, because they did not line up any more. other than that its ok.