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, Ford Engine Mount
Product Details
Brand: Welder Series
MPN: 205017
Country/Region of Manufacture: Canada
Thickness: 3/16"
Used in our urethane bushed Ford motor mounts. Notch in the one side is for a 1-5/8" tube.