Need advice on engine replacement....

[UATahoe]

Currently in the middle of restoring my 87 R10. Nowhere near a frame off restoration, just fixing the worn components and redoing the interior. Currently i pretty much have all of the accessories off of the truck and the radiator is out to be replaced. I am torn on whether i should replace the motor now while i have everything else out of the way.

The current motor was running fine when i started all of the other work. It would smoke on initial startup ever so slightly if it sat a while but other than that no problems. It is the original motor and the odometer reads 85k miles. I know it has rolled over at least once so it either has 185K or 285K on the motor. Should i just leave it alone and drive it until something happens down the road then take everything apart again, or should i just go ahead and replace?

The crate motors seem to be rather reasonable but i would like a little more power too. I am guessing i could buy a new intake for the crate motor and that would help a little. Just curious on others opinions. Any feedback would be great. Thanks!!