The production of modified heavy molecules via thermal cracking (visbreaking) and their corresponding adsorption over macroporous silica-alumina, such as kaolin, is described. The characterization of cracked products in terms of hydrocarbon type SARA distributions and stability indexes (P value) is discussed. Improving the properties of visbreaking products after adsorption over kaolin adsorbent with the quantification of organic adsorbates is presented. Preliminary insights on the nature of those organic adsorbates are described. The feasibility of including an adsorption step after thermal cracking for process improvement is demonstrated in this article.