When we ran a full service chassis fab/turn-key hot rod shop a number of years ago, it was always useful to have threaded things around to weld into the frame for some kind of mount, etc.
Here’s a list of all our threaded things for your reference:
Gusset; for LS/Hemi mounts
Product Details
Brand: Welder Series Inc.
MPN: LS253
Country/Region of Manufacture: Canada
Thickness: 3/16"
Used in the LS250 and 857000 kits.