Transmission is your next choice in reducing overheating. Real time trans temp gauge on the outlet cooling line will tell you when the trans is overheating. There is a company that makes an inline temp probe. The probe is in the fluid path and gives instant temp swings as the transmission heats...
Got a 4.8L Modified intake with a true ram air off grill.
Gutted cat and 3" cat back single exhaust.
20.7mpg driving speed limit
18mpg before
Had 4.3L > 21.5 mpg @ speed limit, plenty of power just won't pull a trailer
I had a 4.3 V6 and got 20 mpg 60 mph. Kept daily log Truck had plenty of low end power and just a little weak passing at 65MPH. Liked the engine.
Got a 4.8 extended cab. Was getting 18.6 MPG lots of passing power but was a heads up match with the V6 at slow speeds. Added a true ram air...
The pulleys run a lot cooler and last a long time. I had an idler bearing on my mower that would only last a few seasons. The thing would get red hot. Took an old plastic idler off my truck and stuck it on there and the thing is still running and you can touch it and don't get burned...