The 787 is my fav motor. Right now, I have 4 of them in my shop. This motor is a very fogiving motor, even if neglected.
Before you elect to replace it, if your capable, you should see if there is anything you can do to save the one you have.
If the motor is locked, remove the head and cylinders to see if you can turn it over by hand. If so, the upper end is in need of attention. To see if you need a cylinder replacement kit, remove the rings and put them into the cylinder, then measure the distance between the rings where they come together. Your clearance should be .013" +/- .003". If this checks out, then check the piston to cylinder wall clearance. You should be getting about .005" to .006"... If there two measurements are good, the cylinders are good, no visible marks on the cylinder walls or pistons, then you might find just honing and rebuilding with a new gasket kit could save you big bucks.
If the compression is good but you have a "ticking" sound, then you likely have a bearing issue in the crank. Again, you don't need to replace the motor, just do the lower end. THere is a crank exchange program with SBT. You can also do this if your having problems with your motor hydro-locking on oil from a bad seal of your rotary chamber..........