I only ever saw one slant six throw a rod. It was in an '80s pickup my buddy was junking. He wanted to see if it would blow up, thought it may go just from holding it wide open. After a few minutes I trickled a handful of small gravel in the carb. Finally it threw a rod out thru the block and the oil that blew out immediately caught on fire. Still fired up the next day to move it out of the middle of his driveway.