A method is disclosed for preparing an elastomeric base composition comprising: (I) mixing (A) a silicone base comprising a curable organopolysiloxane, (B) an optional crosslinking agent, (C) a cure agent in an amount sufficient to cure said organopolysiloxane; (II) mixing the product of step (I) with (D) a fluorocarbon elastomer, (E) an optional compatibilizer, (F) an optional catalyst, and (III) dynamically vulcanizing the organopolysiloxane, wherein the weight ratio of fluorocarbon elastomer (D) to silicone base (A) in the elastomeric base composition ranges from 95:5 to 30:70. The cured rubber compositions obtained from the elastomeric base compositions herein have good fuel resistance properties.