Is there a torque spec for the mounting bolts on the stock pinion snubber attachment plate? I dont see one in the fsm anywhere.

the typical grade 5, 3/8-16 thread can be torqued to 25-30ftlbs.
basically as tight as you can using a 3/8 drive ratchet or standard length box wrench.

Thank you.

Hi Ghost , Factory Service Manual , Section 16 Propellor Shafts and Universal Joints Section . Tightening Reference , Pinion Bumper Plate Screws 7- 1/4 Axle 150 INCH Pounds . Pinion Bumper Plate Screws for 8.75 Axle , 9-1/4 Axle , and the 9 - 3/4 DANA 60 Axle , 200 INCH Pounds Per Factory Service Manual ! Hope this Helps , Ronnie

Ah, prop shaft was a section I didnt think to look. I tried axle and rear suspension. Thanks. (looks like I have them overtightened as I went with the 25 lbs)

When you can't find a torque specification for a bolt in the FSM I usually resort to a reference guide.

Such as

https://www.portlandbolt.com/technical/bolt-torque-chart/

i used that calculator to determine the torque of a plain, [unplated, non lubed] 3/8-16 grade 5 bolt.
it came in as 31ftlb. i had suggested 25-30ftlb.
if i were to be installing the snubber plate, i wouldn't worry too much about what torque value the FSM states. i would just tighten it good with a medium length 3/8 drive ratchet and call it good. having installed [quite] a few of these over a 50+ year span as i have described, none have ever come loose, or have had any bolts broken or stripped threads in the housing.
however, one could always revert to the tried and true method of part installation that has worked forever. "tighten it up until it strips or breaks, then back it off 1/2 a turn."..........[i couldn't resist. ]