Getting Hot on the Freeway

[Mick Je]

Ok, my 1970 GMC has now had all the different cooling ways you can do: The stock clutch fan, Flex Fan, and now electric fans. My truck has a mild 402 .30 big block. My trouble is with the electric fans, everything is good around town, but once I start going over 55mph (spinning 2200 rpm) with A/C on or not on the fwy, the truck eventually starts getting in the 220-230 range and that's way too hot!!! But if I get stuck in LA traffic it cools and runs good! Before I got these fans I did a lot of research comparing other brands and I got the Derale Dual High Output fans (4,000 cfm) with their high output controller. In the future I would like to add a gear vender to lower the rpms. So far I changed thermostats from 180 to 160, then I took the thermostat off and currently trying water outlet restrictors. I was wondering if any of you guys have ideas that might help.

Thanks

These are the fans I have.