The 1950SB is a Federal Mogul bearing, and since it does not have a suffix such as -10, -20, -30, etc. It's probably a standard diameter. The connecting rod journals should measure somewhere around 2.312". The main bearing number doesn't match anything in my F-M shop specifications catalog, but since it also does not have a suffix, it's probably also a "standard" size. The mains get bigger from front to back, so you'll need to measure all the main journals on the crankshaft. I can PM you crankshaft journal specifications and tolerances if you need them. Use a micrometer, NOT a dial caliper, to measure a crankshaft accurately.
Jerry
