Quick ratio steering box - what year? 1976? 1978

[Project1970]

Long time no post...heh.

After a few years of driving more modern cars with rack and pinion steering, I've gotten sick and tired of the original 4.5-turn power steering box in my '70, along with the rag joint and the banged up old steering column. I know I won't get it up to R&P levels of feedback, but I'd like to tighten it all up the best I can, and I figure the best way to do that is to essentially scrap my whole existing setup from the box on up. I know the tie rods and pitman arm are all good, those have been replaced in recent history; the box has been resealed and that's about it.

I've searched over and over again and I keep finding conflicting info on what year I should actually use for the steering box. I'm not concerned with keeping the box compatible with the old rag joint as I'm throwing that away, and if I have to I'm not even worried about changing the lines since I'm already running custom ones with the LS1. I know that sometime after 1975, they went to a 3.5 turn lock-to-lock power steering box, but I see some references to some boxes being variable ratio and some not. Variable-ratio would be nice to have.

So...what's the best bet? As long as the output shaft fits the pitman arm and it bolts up to the frame in the same spot, I'm happy with it.