Jason, they bolted to the subframe and bumper of most cars. They were made by a company called NMW and used to flat tow cars before everyone could afford trailers and also were used alot at the track to pull the car back around to the staging lanes. I am not a fabricator so me building them would be a tough task..... Paul has shown his handiwork duplicating these on another thread

. Click the link below for some information on NMW.
THREAD ON NMW STUFF
Tommy