The CON 3 L40 number is the casting date and would translate December 4, 1950. Patricks catalog, as well as other sources, describes the date code. The first letter represents the month: A=1=Jan, B=2=Feb, etc. to L=12=Dec. 4 is the 4th day of the month. 0 is the last year of the date: (195)0. As Brian said, you received false info about the 4-speed 235 in 1950. Big trucks, 2 tons, had 235 engines standard from 41 - 53. Optional on 1 1/2 ton. It's not unusual for an engine to be swapped. A lot can happen in 50+ years. Now, what 235 do you have. The casting date indicates 1950, which means a Hi-Torque truck motor. It will have babbited rods, unless they have been machined for insert bearings, with the splash & dip oiling system. Unless it's been retrofitted to convert it to full pressure lube by having the crankshaft drilled, etc. Get you a 1950 Shop manual. It will really help. Also call or write Chevrolet for a Restoration Pack. Last I knew they were free. The address has been posted on this forum before. Do a search for it on this site. It is full of useful facts. Good luck!
