Steve. You could buy 2 steel U channels match drilled at least 8” wide. An engineer would have to spec out the necessary weight per foot of the steel. Bolt them to both sides and you should be good to go.
If you mean the weight of the steel per foot I have the book. I could use almost anything, I suppose 3/8 by 6 flat bar the hard way on both sides drilled and bolted through would also work, sq tubing, 4 '' I beam
Problem is the garage door mounting hardware is in the way
What I should do as the car is done and running good is drive it the hundred miles to my daughters house and free up my garage to build a custom gantry, plus I can build a trailer for the machine, that would work well.
Another option i might do is make the gantry were the I beam is bolted to the legs so I can transport it from a shop I can use to my house
