Well I took the van back to the drag strip today to test the new diff.
So much better off the line. Everybody loves it. Managed a new PB too.. shaving those 10ths off..
190 miles done over 2 days.. managed 13.3mpg with.... NO ISSUES!!
I do need to replace the steering wheel for a chunky one as I'm struggling to hold the pencil thin Dodge one without getting pin n needles in my fingers.