Try Michael Butters in Ontario, Canada. Phone 905 372 6926 He has numerous patterns for our cars and will recast levers, etc. in bronze. He did a nice set for me and was reasonable.
The old ones are pot metal and will probably break even if you can find a set.
Hello Charles, Contact Phil Peters in Portland, Oregon. He has knobs for the throttle and spark advance already manufactured and in stock. Contact him at pjpeters@spiritone.com or you can call him at (503) 244-1608.
Do You own a car built by Durant? Yes, a 1929 Durant model 60 DeLux 4 door sedan.