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:
Rear Spring Hanger Main Plate
Product Details
Brand: Welder Series
MPN: 20951
Thickness: 3/8"
For a 3" diameter axle tube. Center of the spring will be about 6-1/8" behind the axle tube.
