You might want think about an overdrive. My first car was a 63 Rambler classic, with the under square 195.6 I6 engine. Your engine is over square. The later jeep 4 cylinder engines are AMC, 86-2001, 2.5 liter, unfortunately they are over square also. I just rebuilt one this past summer, a fairly simple engine with a few quirks. You will have to read up on bell housing compatibility. (as you might guess, I prefer under square engines)
Boys and girls, this is what happens when your wife drives the jeep home with no coolant: AMC I4 cracked head and a hole in #3 piston
MORE INFO:
http://en.wikipedia.org/wiki/AMC_straight-4_engine