I thought the 318/340 crankshafts were both SMALL Journal Mains and the 360 had the bigger Mains. With this being the case that 318 could VERY well have a 340 crankshaft in it, but like stated earlier it would not be a STROKER being that the 340 Stroke is the same as a 318. I know that a 360 Mopar Performance Crankshaft comes in Large and Small Journal Main sizing. I have one with the SMALL mains on my parts shelf.