Should work, Car Craft mag has done a few Vortec head based builds in the past few years. Make sure to avoid Gen II series heads, they have reverse coolant flow. The 400 was produced from '70 to '79, the vortec heads were produced nearly 20 years later, so there was no factory combos. Remember Vortec heads also require and Vortec style intake. For a street motor, a mild vortec set-up should do very well, plus you have the possiblity of using factory fuel injection.