the only place iron is better in an engine is the part the piston slides up and down in. the aluminum heads are just straight up better for an n/a car with the correct timing tables and quality fuel. having consistent combustion temperatures from reverse flow cooling and aluminum heads were a huge advantage in this era engine to how much timing advance you could run and how much power you could make. if the b-body rig was better it would have made more power than the aluminum head version -- and it did not.