If you're missing the stop let me know and I'll send you one. It's just a 5/16" bolt with a washer brazed to the head and yes that's original spec. You can see it in two views here.
Gas Pedal [427 CCX Contemporary] - $250.00 : Acton Custom Enterprises, Custom Metal for Cobras
Check also you have a return spring on the carb and another one on the pedal.