I've never heard of a 413. What do you know about them? RV motor?
They came in a number of early Mopars.There was a high performance 413 and a truck version of the engine.
Raised deck block like a 440, same stroke, smaller bore.
They were used for years in industrial trucks long after the 440 came out.
There are NO off the shelf performance pistons for them. Custom is your only shot.
https://www.youtube.com/watch?v=shjAbWfjH0k :2thumbs:
https://www.youtube.com/watch?v=KhdlV1LbBP0&ab_channel=robjulian