Over heating on the freeway?

71 dart, new 360
New griffen cross flow radiator. Restrictor plate in T stat housing.
Large eletric puller fan and shroud.
All new hoses.

The car is fine around town, 180-190 but get on the freeway and the temp just cimbs...

This is so backwards from all other cars I've ever owned I'm not sure what gives?

Any ideas?