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:
Spacer; 3/4" OD x 1/2" ID x .340" Long
Product Details
Brand: Welder Series Inc.
MPN: BLAS0210
Country/Region of Manufacture: Canada
Thickness: .340"
Bolt Size: 1/2"
This spacer is used when installing our small block Chrysler engine mount kit on a 360. Two required to go between the ear on the block and the engine mount.