Summing-up the Pros & Cons:
Man, there are all sorts of opinions out there on which axle is best. One can easily become overwhelmed sorting through all the pros and cons of each.
Guys with D60s brag of their after market support and various selections in gears and lockers. The other axles are too heavy or their diffs are too big and rob you of ground clearance. The cons being that if you do need to bore out your spindles, it'll cost you extra to have it done correctly or you run the risk of suffering potentially serious consequences. You can take your empty housing to a machine shop that has a lathe large enough to spin the housing or cut off your spindles to have them bored out and then re-weld them to your housing which requires special tools. You can also buy, rent, or make an improvised tool that'll allow you to bore out your own spindles. In a weight comparison between comparable axles (14B, D70, etc.), all with disc brake conversions, it would be the lightest. However, pinion deflection seems to be an issue. I'm no expert, but I'd venture to say that you'd probably require aftermarket (14B, D70 or 9") spindles if you wanted to run 40 spline axles and that may complicate a disk brake conversion option and it better be done right! (Oh geez, that's another can of worms 40-spline axles and drive flanges being strictly for off-road, comp rigs only!) Nevertheless, I know some folks who beat their junk pretty regularly and have no quarrels with their bored out D60s.
The guys with 14-bolts say there's is better than the D60 because you can find them dirt cheap everywhere, they don't have to bore out their spindles and they already have 1.5" diameter axles (I believe even the 30-splines are 1.5" diameter), their $hit is super beefy and easy to work on and after market parts are relatively cheap. A CUCV find may also net you a Detroit or Gov-Loc (Is there a difference?). They also have the extra pinion support which is truly an added plus and their gear and locker selections keep growing. The Eaton is cool as hell with its smaller housing and drop out third but they're obviously rare and would require some custom work (something about the side gears requiring mods). Ballistic Fabrication is working on a new 14-bolt housing and Portal-Tek now has their new Super-14 drop out third member. It's $1,400 but hey, folks are paying top dollar for True Hi-9s.
Guys that opt for the D70 claim the 14-bolt's an anchor. The guys with the 14B will counter that they can shave their housings and even their rings! (That kind of takes away from their arument of having a larger ring.)
Looking at the February 2010 issue of Petersen's 4-Wheel & Off-Road, the American Axle Manufacturing's (AAM) 11.5" ring dwarfs the 14-bolt's and Ford Sterling's 10.5" ring. The tooth surface contact on Sterling's pinion dwarfs that of the 14-bolt's, but the splined shaft portion on the 14-bolts pinion appears thicker.
14-bolt and D70 front axles, Yota axles, D80s, MOGs, Rocks, Portals, 609s, where does it end and who really gives a $hit? They each appear to have their own pros and cons with money savings being the primary factor for most. If I had nothing on-hand and money was an issue, I'd opt for the 14-bolt for the reasons provided and because I like the GLO pinion guard that I run on my 9". (That thing has taken a beating and probably saved by drive shaft a number of times.) Now that leads me to the 9". If my 9" was full-width, I'd keep it! It's large pinion contact, extra support and third drop out are all pretty sweet. However, having to go with a matching full-width front end I'd need new axles and since my Currie's are 31-splines and I'd being opting for 35s or 40s, I'd need a new locker as well! Damn if one thing doesn't lead to another! The 9" has a HUGE after-market and custom, stupid HD housings are available from just about every reputable manufacturer!
My goal is to stuff a pair of 40" MT/Rs or KM2s (Used, those are some pricey boogers!) under my hydro-assisted, dual purposed Bronc. Yeah, cruising topless in my baby during the summer is wicked cool. I already have a freak'n D60 so if it's gonna cost me ~$100 (hopefully less than that) to bore out the spindles, then I'll probably proceed with the build because that's what I have and because it closely matches my front axle's WMS.
Let's see how it goes...
