I'm just giving my experience and not "telling" anyone what to do.:yap:
That 8.25 should work with the front shaft,as a rear.
Do yourself a favor and run your drivtrain without the driveshafts a check for runout which could be source of vibes.Because you are only lifted 4.5 and have the t-case tail cone support I'm surprised you need a SYE.My 87 never needed even with 6" lift.
It will run smoother with the SYE though.
RE h-n-t recommends making a drill guide out of your slip yoke.I made a better guide with bushings for both drill and tap and also use a Q (.332)drill instead of the:huh: 21/64 th's(.328) drill in the kit.The +.004 diff is important to tap the lightly heat treated tailshaft.
And don't drill a small pilot hole.I drilled,drilled,drilled and said oh yah, I'll do alittle with a pilot,then Like drilling Brass(never ever use a pilot hole) the second drill caught and broke off and I got lucky that it came out easy.(pissed off bigtime):flamemad:Just be patient and clean often and use lots of oil frequently.
Small tap handle also for clearance or drop trans support down alittle to give room.
Also don't put the red locktight Untill you test fit(check that your taped hole is deep enough) and are happy with everthing.
Hope this helps anyone doing this job.