Well first it a shame not to be able to use it NOW. For our spare race engines we would back off the valve rockers so it does not sit with springs compressed and valves open. A squirt of
oil in each cylinder and then replace the spark plugs. The plugs in bottom of block near pan rail are replaced with petcocks so coolant can be drained from block easily.
I might be tempted to rotate the crank each month or so just to keep seals moist. Compression will leak past rings without valves open as you bar it over. You could also give it to a buddy to run the dog snot out of it until you are ready for it.
