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:
Frame Bracket, Model A rear four link
Product Details
Brand: Welder Series
Thickness: 3/16"
Hole size: 2 @ 5/8"
Use on Model A frames made from rectangular tubing with no taper when viewed from the side.
Use with #10767 spacers. Designed for 1-5/8″ diameter urethane bushings. The upper and lower bar frame mounting points will be perpendicular to the bottom of the frame rail.