They are hard to find I ended up making one I now have a long original for my dirt set up and a short one for my sumo set up
I took a piece of 1 x 3/8 flat bar and ground it down to match original and drilled a hole on it
Tig welded it onto a piece of 3/8 schedule 40 pipe and tig welded on a washer for a foot and a piece of tig rod for the spring hook up.