In order for me to upgrade my fuel injectors on my 91 Cherokee Sport, I had to procure the following items per the Jeep Service Manual (Engine, Chassis, Body - Fuel System 14-9); one 3/8 inch dia. quick connect repair kit #83504447 and one 5/16 inch dia. kit #83502745. The 3/8 inch is no longer stocked at dealerships. I found the aftermarket (Crown) to not meet specs. In my case it cost me $400 because the aftermarket repair kits did not fit the fuel line (intake needs the 3/8's inch kit) and I had to rent a car while my Jeep sat at the repair shop while they researched which dealerships in the USA still had these parts in their inventory. There are still a few kits available at a dozen or so Jeep dealerships but the cost is not cheap. These kits position the two o-rings and spacer as well as the snap lock that fits into the fuel rail when connecting the fuel line and return line.
The Crown 3/8 dia was .008 oversized when measured against the Mopar (dealership part) kit which explains why it would not fit. The Crown 5/16 dia. kit was .003 oversized when compared to its equivalent dealership part.

 

I used a cheap plastic set from oreilly's to disconnect the fuel line from the rail ( i think it's 3/8ths). Same set I used on the a/c line. I think it cost me $5 or $10. It looks like this

http://www.harborfreight.com/6-piece...ool-97576.html

 

Fuel disconnects

Quick disconnect part numbers

The Napa part numbers for just o-rings *is:

Napa 730-5018 3/8 Viton individual o-rings
Napa 730-5017 5/16 Viton individual o-rings
Napa CRB 212305 fuel line repair kit 5/16
*Remember to re-use your old spacer between the 2 new o-rings!!

Mopar repair kits:

83502745 fuel line repair kit 5/16
83504447 fuel line/Trans line repair kit 3/8

 

Just found a Mopar 5/16" kit on ebay for 25$
http://www.ebay.com/itm/like/3506614...&ul_noapp=true
Mopar 3/8" kit for $15
http://www.ebay.com/itm/MOPAR-835044...5YuKAM&vxp=mtr