HUH ? AHHH BULL-DUNG !
He might know his vehicles, but he obviously doesn't know mopars.
The "Renowned for leaking" statement is strictly "Verbal Diarhea" and nothing more, Mopar Engines can be/are some of the best sealing engines around when done properly, and thats the key, even when using synthetic oils which are known to leak out where Dinosaur oil won't.
Tip; when re-installing your rear main seal, cut the seal retainer approx. .010" on a cap cutter to add a bit of crush to the seal. Also, "take a boo" at the seal as installed in the block to insure it's centered on the crank. Some blocks have the seal recess in the block machined slightly offset, which provides loose seal contact on one side.
If you find this problem, install the seal with the ends staggered across/over the parting line, and "drag" the seal over for better contact with the crank on the offending side when installing the retainer(bottom half).
Finally, use a good bead of silicon and a wet finger to seal the retainer at the rear of the block "all the way around", having brake-cleaned thoroughly first of course.
Renowned for leaking, MY ARSE ! oops ! that does leak occassionally !