True !
But if you for some reason don´t want the aluminum heads, but want the power from the L-88´s cam, pistons, intake, carb etc. Then you put iron heads on it an get an "all iron L-88"
I believe the last -71 LS-6 Corvettes were sold with iron heads for 600$ less, and they were still considered to be LS-6 cars.
Anders