1971 was the last year for the Jeep offset rear Dana 44 it's also a flanged Dana 44
good axle. You can't run a Dana 300.
Your best bet is to sell it and buy a later 72-75 CJ5 longer hood and wheelbase by 3" Then you will have a centered flanged Dana 44 then you can run a Dana 20 or Dana 300
I had a 71 CJ5
Rubicon Rich ,05 TJ Rubicon: PatriotJeepers.com
86 CJ7 258,T18,Scout Dana300,twin sticks,Dana44's,4W Disc, locked,35's,YORK OBA,Warn 8274,fullcage.
51 M100 1/4 ton Jeep trailer