The red head went on with a psc pump , lml booster , gas truck cooler and synthetic ps fluid. Im now at 112k miles and just swapped the redhead for the hd PSC XD steering gear and have 34.5" tires. I still cant turn lock to lock when at a stop but i can turn more than i could with the redhead. The trucks steering now consists of Lml hydrobooster
PSC makes a heavy duty box. They're proud of them, but my buddy that put one on his LMM dually with oversized tires on it says it drives and turns better than stock.
Nothing beats PSC's box and pump. The pump puts out higher flow than the GM pump and their box is the only actual upgrade over the OEM box. The internals in the PSC box are bigger (shaft, bearings, gears etc).
We only use and install PSC boxes in these trucks. The PSC boxes seem to hold up the best in terms of tightness and the steering effort feels reduced compared to an OEM box.
Ive seen really great results with ATF+4 in Saginaw systems in jeeps (stock parts, AGR, PSC, ghetto rigged setups...) the ATF+4 always reduced steering effort and never boiled over. Just looking at published numbers, the redline ATF C+ may be the best fluid out for power steering.
get with lance at PSC he will take care of you. with 40's you have to do something to the steering your stock gear box won't handle that, although your stock pump should be a saginaw which is plenty.
I've went though several boxes and pumps on my LBZ. Currently running a blue top that seems to be developing some play in it. I've done the LML pump upgrade once and even it died after some years. Went with the PSC pump this last time about a year and a half ago and by far the best results.