I've had this sitting (on end) around for years and belive it is a 340 forged crank. I can not find any casting numbers on it. I took some pictures on a little inspection jig I made for your viewing. Mains are 2.50" and Rods are 2.123. I don't have anything to measure the stroke. Make me an offer. If you guys think it's not a 340 I'll take it off the board.