Will the CheaTR cam work with the new 918's?
 

Title basically says it all. And is the base circle the same size as the stock cam?

Yes as long as you do not have big valves and that your seat/open pressures are within the cam's requirement. (this may require shimming)
No the CheaTR is dual lobed with 2 different base circles, both smaller than stock.

In my experience, stock LS cams have had about a 1.53 base circle. The aftermarket cams i have measured (low 220s duration) have been 1.48 or about .050 smaller.