I have heard all sorts of different numbers about how long I should wait to use synthetic oil in my brute force. It has around 40 hours and 300 miles, is this enough to switch? I want to switch to help reduce engine heat as much as possible.

 

I think you're OK to switch.
A good article: http://www.allsyntheticsgroup.com/break-in.html

 

Thanks, that was an informative article