There are many D44s out there. Chevy, Ford, Dodge, Scout and Jeeps came with them. The one that is somewhat a direct bolt in is from a 78-79 Ford F250. Ones to avoid are the cast wedge D44s from Ford F150 trucks (76-77 were welded wedges and are usable). Ford D44 are desirable for the Jeep crowd that wants to keep the driver's side drop and they're stronger than passenger side drops due to them being high pinion vs low pinion.
Whether a built Dana 30 like 4Jeepn mentioned will hold up to a V8 conversion depends on your driving style, whether it is locked or not and what size tires you plan to run. A low geared D30 will shred the R&P with big tires and extra power behind. Additionally, that AX-5 transmission will not likely hold up very long to the extra power of the V8. If you're running 33" to possibly 37" with a V8, then the D44 is usually a good choice. Of course, if the bigger the tire, the more you need to baby it. Running tons (D60/14b etc) on anything less than 37" tread and you're losing major ground clearance.