The only reason i am doing non-adjustable links is because of my past bad experience with adjustable ones...
But, i must say that my last suspension probably wasn't designed the best, it had bind in some of the joints at full flex and droop, therefore it bent the threads on the cheap masterCarr heims i used to use. (you get what you pay for in this industry.) I replaced all of those heims on that rig with weld-on johnny joints, therefore ending my bent threads issue. A better way to get rid of that issue would have been to redesign the mounts.
Since then i have learned to better build suspension systems, and without bind, im sure i would have no problem with even the cheap heims. I wish i had made my current link adjustable, as im sure once my rig completely settles, i will be probably an 1/8 to a 1/4 off somewhere. But, I'm big with peace of mind, I know that i will never have a joint failure due to threads failing, or a bung failing, or threads in a bung pulling out, etc... and like Brad said, after 2 trail runs of those lower links getting pounded on rock ledges... yer not gonna be able to adjust them, they will be set where they are.
But, my suggestion, build one side with a forged threaded johnny joint, the one with the forged shank, and build the other end with a weld on. Put the threaded one at the chassis, as it will see way less stress.
these come in 1"x12tpi and 1.25x14tpi, use these for threaded.
And go with the 2" joint like this at the other end...
the 2.5 and 3" joints are HUGE and you will have difficulty fitting all the mounts you need. I used the 2" even on my lower 2" arms. I had the end machined down to 1 5/8 so i would have some bite for a weld. the reduced thickness there is not an issue, as at the ends, the only issue is shear strength, not bend strength. MOI is no factor at the ends.
You can see the turn-down in this pic.
[img]http://www.schoolboy*****.com/ImageFolio4_files/gallery/Members/Carwash/Off_Road_Pics/06_Crawler_Build-up/06buggy_257.jpg[/img]
Long winded, sorry.