A reduced cost elastomeric blend suitable for use in vehicle timing belts and other applications constructed with elastomeric portions having a high HNBR concentration. The blends comprise from about 50 to less than 100 phr of HNBR and from about 0.1 to about 50 phr of lower cost diluent unsaturated nitrile rubber with from about 0.1 to about 30 phr of a heat resistant additive, which may be THERBAN HT. The elastomeric blends may be cured with a peroxide/co-agent cure system. The elastomeric blends may be mixed by a Y-mix method to improve ozone resistance. A timing belt constructed of the elastomeric blend is also taught.