Difference between 741 and 742?

You can put any 8.75 RING gear in any 8.75 case, they are all the same for a specific ratio.

How would you put a 489 or 742 pinion in a 741 case when the OD of the tapered cup for each is .5" difference? The 489/742 OD is 3.5", 741 has a 3" OD. Maybe if there was some sort of special ring to put that bearing in the 741 case. The 489/742 bearing is too large to fit in the 741 cup bore itself, IIRC.

Look at the pic in this link that has the bearings in front of the pinion

http://www.moparts.org/Tech/Archive/axle/1.html

Maybe if you could bore the 741 to accept the large tapered ring.

It's really much ado about nothing. The 741 isn't weak like that stupid article on the net implies. The pinion and bearings ARE NOT the weak link in the pumpkin!