Intake Manifold Heater Hose Connection

On 69 and earlier intakes the heater hose connection fits a 5/8" heater hose but on the 70 and later plus most aftermarket manifolds use a 1/2" hose. Since my dart is a 68 both heater hoses are 5/8" but my air gap has the opening set up for 1/2" hose does someone make an adapter that goes from 1/2 to 5/8?? Or what else works??