Just FYI's LBZ+ dont see much of an oil temp issue influenced by twins nearly as much as LB7/LLY. Like Pat said, a poor mans oil temp gauge is to watch the oil pressure gauge. With my twins, before a cooler, I could see 270* towing up 6% grade for 5-10 miles. Oil pressure then would be ~30psi @ 2500rpm. Highest vie seen with a cooler is 225* towing 13k to Mike L's.
Those with AC issues, have you removed the charge, and added the correct amount, or even serviced it at all? Proper AC maint. should be serviced every year. I dont have any AC issues, 110* plus here.