The 580D is no bigger than the previous 580C. It was the same exact class model, except revamped. The differences to the D vs C, one was New Cab Style, Clutch Cut-Out Button on the Loader Lever, and improved hydraulics. The backhoe attachment was exactly the same, the loader was exactly the same.
The 480 Class has been discontinued in the end of 1994. In 1995, the 480F was completley gone along with the 680L. The new L series came out in 95, and that lineup was, 580L, 580SuperL and 590SuperL. However, the 480's were out, the same time the 580's were out. Original 480 Class, was the 480CK (construction king), then the 480B, then the 480C, 480D, 480E, 480LL (landscape loader) then finally the 480F(which was the last 480 produced)..
As far as the cummin's diesel engine you mention, the 580E was the first Loader/Backhoe to have this engine. The 580D was not, the 580 Super D, was the first Case Construction King to offer 4WD, with more HP, but it was a case engine.
When it comes to Case Backhoes I know them by heart, I am like "Rain Man" on this subject. I have every Case Brochure from when the construction king was introduced in 1957. As a Kid, I've studied the facts and figures on these machines, and I grew up using them all, as each model came out because of my Dad's Best Friends Backhoe Business. I was a hooked on Case kid.
The 480B, and the 480F were the only 480's to have the "Reverse Power Linkage" design on the loader buckets like all the 580's had. The Reverse Power Linkage is a great design that is exclusive to case. The other 480's had straight piston to bucket connections, similar to most Compact tractor loaders. What is great about the Reverse Power Linkage is super fast dump cycles, and more breakout power when curling the bucket. When dumping the bucket, with power linkage, the small end or fast end of the cylinder is used. When curling the bucket, the power end of the cylinder is used.
The 480D was the first 480 to have the Over Center Backhoe Design which was great for transporting the machine, because when in Over-Center, the weight of the hoe was aimed toward the center of the machine, and also provided excellent clearance between groundline and backhoe bucket. And of course this made the overall length of the machine shorter. This was another case exclusive. The 580B was the first Construction King, to incorporate an Over-Center Backhoe design. All of the 580's from 580B to 580E, incorporated twin boom cylinders, where all of the 480's had just one boom cylinder mounted to only one side of the boom.
580K was a completly revamped design all together, it had just one very large boom cylinder, in a totally redesigned cast ductile Iron boom. This is still used on the Current 580M's.
JCM's 480 has the optional 14' hoe. Case offered 3 hoes for the 480D, and the 480F.
12' standard (non-extendahoe) was the standard hoe.
14' optional (non-extendahoe) Longer boom, same dipper as 12' foot hoe.
and of course they offered the Hydraulic Extendahoe which had the shorter boom found on the 12' standard, but had the telescoping dipper that would extend to (12' to 15') digging depths.
If anybody ever has any questions about any case backhoe feel free to just ask me. I have most of the answers right in my head, and of course like I said, I have every manual, and brochure on these.
