I respectfully disagree with this. In an absolute sense, I agree. However from a cost/benefit perspective, I do not. The original 273 heads have the smallest combustion chambers of the heads Chrysler made for the LA engine. I'm slow to recommend new heads primarily for this reason. What I do recommend is that if hardened valve seats are not in the head, install them. Secondly, determine if the head has been planed, and if so, how much. If the head has been planed, I recommend shimming the rocker shaft an equivalent amount to restore the rocker arm geometry, which reduces wear on the entire valve train.