The 530CK and the 580CK are based on the same tractor platform,, the 530 utility tractor, the 530 can have either a dry clutch or Case-O-Matic drive. the 159 Case gas engine was std with the Case 188 dsl as a option, loader is the same basic model on both 530CK and 580CK, engines are also the same choices, the big change between a 530CK and 580CK is the backhoe, the 530CK has the design with the boom cylinder enclosed in the boom mast, the 580CK is a external design and is a stronger more productive backhoe,, both are perfectly fine for what you are wanting one for. the extra weight is the backhoe between the two. the 580CK also introduced the power shuttle where the 530CK has a mechanical shuttle, again both will do the job you will be asking of it just fine. We sold hundreds of 580CK from 1966 through 1970,( we sold the 580B/580C also through 1976) Every 580CK we sold had power shuttle,, Best setup that was available and was just one thing that put Case in the #1 spot for TLB production,sales and resale value which they still hold today, I use my 580CK year around in temps down to -80F with Zero problems,, of course you have to let it warm up 10-15 min when its that cold,, like any machine,, parts are around for either model,, the bulk of them we sold was in the oil field, there is not much tougher place to be a machine than in that app, some companies here owned 25 580CK's in those days,, as far as splitting them they both split the very same way,, I never remove a engine to work on a shuttle on them but just split and roll the rear axle/trans unit out the rear, I can have one torn down in less than 2 hours,, and that includes removing the hoe and backhoe mounts ect, of course both the 530CK and 580CK can be bought with a dry clutch,, for loader work I will take a power shuttle over a dry clutch any day built they made both depending on what your likes was. a 580B is the same basic tractor and loader,, with some tin work and operator platform changes, and the "B" has the over center backhoe design which is far better balanced for roading,, and had a factory cab with ROPS option,, a 580C was a complete redesign and is what is still being built today,, hope that answered your questions if I forgot something just ask,, I am glad to add more info/data