If you have no heater box, you have no defrost either, I hope you live in Arizona or southern Texas. Here in VA, we have to have defrost in order to pass annual state inspection.
If you don't need it cap off the intake and at the radiator.
SgtDel
aka "Andy"
www.delbridge.net
1979 Big 10 383 stroker
1991 Blu 'Burb 3/4 ton 4x4