Our early L260's have the 'cartridge' style. Napa had one on the shelf for me. If they can't get it, they can cross reference another number for you. (Baldwin makes one)
Shorten your 'Long Bolt':
Remove the entire filter housing from the engine block with the 4 bolts.
Remove the long bolt that runs through the filter. (note the filter number and post it here please)
Grind off 1/3 of the head of the long bolt (tube)
Grind off some of the threaded end of the long bolt. (about 2-3 threads of length)
De-burr long bolt and rinse in diesel.
'Dry fit' the whole housing to make sure you took enough length off the long bolt. You should be able to barely unthread the long bolt and remove the cartridge with the housing still mounted to the engine block.
Semi-Pro tip: if you can, get a nut that fits the threads, spin it onto the long bolt before you grind the threads off. Then when you twist the nut off it will un-foul your threads and your life just got a little easier.
Cheers,