How do you tell the diff. between a CJ-5 frame and a CJ-3B frame.

OK, If all that you are looking at is a frame, transmission, X-case, front and rear end, motor and steering componates how do you tell the differance from a 1961 CJ-3B and a 1959 CJ-5?

 

Here's a look at flatty frames:http://www.film.queensu.ca/cj3b/Dating/DatingFrames.html
AFAIK, the 3B retained the round front crossmember under the rad, while the '5 was always a channel style, never round.
Here's another look at it :http://www.film.queensu.ca/cj3b/Tech/FrameCJ5.html

 

Time to throw in a wrench....

My '61 CJ-6 had the round style front crossmember. It is a right hand drive, though (made for export, I believe.)



Regardless, the first responder is correct...look at the crossmember. I have an oddity.