I'll say this though, oil weight may not do jack if things are too worn out in the bottom end. My girlfriend's father has a '68 Ford Galaxie he lefts lets me drive, which used to bottom out near 0 oil pressure at red lights. I know its not a mopar engine but my point is: new oil pump, no leaks, and we tried 20w50: got us up to about 5 PSI at the red lights. We live with it, but I'm just saying viscosity won't always make too much difference.
