I'm looking for OE or exact repro for a 1971 383 air Grabber set up. have no idea what the wing nut looks like. What's the thread pitch for the piece of threaded rod connecting the carburetor to the cleaner lid? If it's 1/4-20, I'm looking for OE/ repro, if it's another pitch, I'll have to jury rig something because I'm using an Edlebrock 1407 carb but using the original Air Grabber baseplate so the rod has to fit through the brace that goes across the centre of the baseplate.