A brand new short block should have a new rear main installed. You will need the timing cover seals as mentioned along with the front main seal (harmonic balancer seal).
Make sure to check to make sure they include the valve cover spark plug hole gaskets as my first set of valve cover gaskets came without them.
Cam retainer bolts. They're torque to yeild and snap off very, very easy. Hard bolt and soft metal head castings makes it a bit harder to drill it out and re-tap too.
Water crossover tube gasket ring. It's just a small rubber O-ring, but worth replacing because it can cause a major coolant leak if you rip the old brittle one.
Good time to change the PCV valve and breather too (I think the new short block comes with a breather IIRC though).
The fuel coupling tool and the balancer puller can be borrowed from AutoZone or just about any other parts store with a tool program if you want to save a couple of bucks.
Hoists can be expensive unless you plan on pulling a lot of engines too, they rent for $10-$20 a day at most rental shops.
That's all I can think of for now... Good luck!
