This might be an idea. I was looking through mu books and noticed that a 383 and a 426 wedge have the same bore 4.250. I don't know if everything else is the same too. Mopar wqs known for just changing the stroke to change displacement. Might be something to look at for an off the shelf piston. Stock 383 bore would be like .062 over for a 413. Just an idea.
TopHat
