This came off a 1940s 216 or 235, but will fit all 216/ 235/ 261 "stovebolt 6" engines. 5/8" pulley. 7.25" diameter on balancer wheel, 6" diameter on pulley. See pics for exact condition details.
WILL MOST LIKELY NEED A SLEEVE FOR ANY NEW INSTALLATION. These are notorious for wearing down around the seal on the timing cover and usually develop a groove in the shaft. Repair sleeves are available from RockAuto or your local auto parts retailer, usually under $10.
Check my other listings for more 41-48 Chevy car and stovebolt engine parts.