Find a bolt which fits and take it to your local auto parts or hardware store as a sample. I don't speak inliner but 289-302-351 etc. use a 5/16" NC thread in the manifold. The top of the stud is usually 5/16" NF (better vibration resistance). You can use the right size and thread pitch all-thread in a pinch. Bolts work too if they'll clear the carb.