What model and year Jeep? and what are you trying to do with your Jeep?
If you use the T18 (6:32 first gear model) not the 4:00 first gear and bolt it to your Scout Dana 300 (2:60) you will have a great low range.
The Dana 20 only has a 2:00 low range.
If you put the dana 20 and the Scout Dana...