I found a better picture. I guess it would be called a pedal stop.
By your question, I’m guessing yours is missing and you want to make one. So since we’re in quarantine and it’s raining buckets here, of course I can take it off to measure it.
To make it you will need:
1 flat washer 1-3/4" OD x 5/8" ID x 3/16" thick
1 hex coupling nut 3/8-20 BSF x 1-1/2" long
1 threaded stud 3/8-20 BSF x 3-3/4" long, threads 2-3/8" and 5/8" long, 3/4" unthreaded.
2 regular 3/8 BSF nuts
1 thin 3/8 BSF nut
1 helical lock washer
The coupling nut is machined down at one end 5/8" to fit inside the flat washer.
The flat washer is welded onto the coupling nut at an angle of 3 degrees, but I can’t say if that is intentional or workman carelessness. Maybe intentional, the idea is so that the pedal arm will contact it at the same angle. It’s welded with an 1/8" fillet on the outside, I suppose for better strength, as it sees some stress with a driver having a heavy clutch foot.
Part number? Nope, can’t find it in any of my parts books.