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:
Top plate
Product Details
Brand: Welder Series
MPN: LS252
Country/Region of Manufacture: Canada
Thickness: 3/16"
Length: As reference grid
Plate used in Welder Series LS and Gen 3 Hemi engine mount kits.