Thanks, no slits or vent holes yet but I've ran the truck at the trials climbing hills and trail riding 4-5 hours at a time and didn't notice any temperature change.

 

BTW my truck was the perfect place to test the covering of the wheel wells around the engine bay cause I have a superchargers which produce excessive amounts of heat. I'm happy with the turnout I don't think I'll need vent holes.

 

Thats good.. guess the fan is strong enough once it kicks on to keep it cool. Howd the covers do keeping the mud out on the runs?