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 1" Tube
Product Details
Brand: Welder Series
MPN: 216352
Thickness: 3/16"
About 2" long. Designed to be used with #216351 transmission mount. Grid is 1″ x 1″.