Correct, there is just one 413 that shares a casting number with a 426 and it's an industrial engine, or it came in heavy duty trucks, meaning larger than a pickup truck. The chances of finding one are rather slim.

Here's the important point: The quote is referring ONLY to those blocks with that casting number. He is not talking about ANY OTHER 413 block.


Now that ultrasonic thickness testers are common, we are discovering how bad the Mopar blocks really were. It's a fact. Also, we're discovering that cylinder wall thicknesses could be all over the map in the same block.

IMHO the largest a 413 block could be bored to is 4.250. The blocks have such a low value that if one is bad you can always do another, although the price of boring another 8 holes may be more than the price of a sonic check.

R.