I was in the same conundrum. (warning, long post)
My stock (72) box seemed to work ok...not tons of play but some and I felt it could be better....but it leaked bad. I had tried using Lucas oil's "stop leak " fluid which was "guaranteed to work" but it didnt...LOL...so it musta been a bad leak.
40 years can do a lot to seals.
I am rebuilding my front end and had everything apart and didnt want to have to rip it all apart again so figured I would do "something" about the box.....a "do it once" attitude.
Well, the rebuild kits I found were around $75-100 (unless I was looking at the wrong things) and I realized that I knew nothing about the guts of a steering box. The cost of an already rebuilt (stock) box was about $220 or so.....and a Firm Feel or S&G unit was "only" another $120 or so. I didn't care for how light the steering was, so I decided to hitch up my big boy pants, bite the bullet and pull the trigger (is that enough cliche for one sentence? LOL). I am about $420 into the box what with shipping both ways. It was a blow to my budget for sure but I think it wa the best choice.
I went with Firm Feel simply because they seem to have the best record here and elsewhere......
They were SUPER responsive....they were out of the earlier small sector shaft cores so they had me ship mine to them first and they rebuilt that one.....which is cool cause I can say its the original one. The didnt seem to feel that the change to a large sector shaft box would buy me much aside from a cheaper pitman arm (the 72 and down pitman is like $150 vs $50 for the 73-up....)....but they will not send you a 73-up box if you send them a 72-down core.....I would have had to find a 73-up core or pay the core charge, so it would have been a wash......plus I found that the pitman for $109 at PST thanks to folks here......so still saved some money.
The core charge is enough that you will want to send a core to them to save the cash (I think it was $80) so might as well get mine back I figured.
I went with stage 3 and clear coated it when I got it back. Stage 3 because it sounded like Stage 1 was more or less stock....stage two was "just a little firmer" and stage 3 was "more like todays perf. cars".....I am running skinny front tires (relative to the back and I like a heavier feel to begin with.
I installed it about a month ago but have not even fired it up yet...still assembling my front end. They cleaned up the box real nice and I was very pleased with thee experience to this point.
Frankly, I wouldn't mess with rebuilding it myself unless you knew what you were doing...what to look for as far as worn hard parts, clearances, etc. Getting the box in and out is too much of a pain in the behind to do it more than once if not absolutely necessary IMHO especially if you have headers.
I am just crossing my fingers that it is 100% perfect when I fire it up...LOL
Good luck in your decisions!
