Aluminum heads run cooler than steel, but the thermal expansion corfficient is more than 2x steel. My Chevy 502 manual says to retorque the factory heads after the first 30 mile break in. If I were you I would plan on doing it. At the very least check a few each side that are of easier access to see if the torque has changed. Be sure she is cooled all the way down before checking torque!

It also came with ground washers to use under the bolt heads. These are critical to assure proper clamp loads are achieved with minimal distortion and damage to the head bolt spot face locations.

As long as you don't overheat the motor badly the heads will be fine. If you ever do over heat, allow the motor to cool down slowly and avoid dumping cold water into the rad and engine. This will usually cause the aluminum cylinder heads to warp badly. Will also destroy some cast heads by the way.

Regards, Kitz