I did not make the comment but part of the answer is strength, the pinion is smaller in diameter. But for me the availability of new gears is limited to 2 ratios, 742 a few more, 489 even more
As for housings... How much putting can you stand? I have now bought 2 housings one is a So Cal housing no putting, but some numb nuts used round (not OEM flattened) u bolts and crushed the tubing, (I bought it seeing photos only) the second one had wear from loose OEM u bolts, I paid 650 for the first one (it was my first purchase and I did not know what to look for) 500 for the second but I can use it as is.
