School me on xr500's

I have a complete engine coming in the mail. What should i look for on the tear down? Any things to be sure to check or replace? I know these xr motors have a great reputation as being reliable and stump pullers. Any tips and tricks to get the most out of it? I plan on running it hard as its goin in a light xr100 frame to be a street tracker. Any help will be greatly appreciated

Oh and its a 1979 xr500 engine thats not running nothing else known about it besides that.