Provided are blends of branched hydrocarbon comb polymers having tailored branching and molecular weight parameters, with substantially linear polymers. Such blends have been found to have improved extensional rheological properties, while maintaining nearly the viscosity of the substantially linear polymers. The blends of the hydrocarbon comb polymers with the substantially linear polymers thus maintain the extrusion processing characteristics of the linear polymer alone, but have improved extensional flow processability, with strain hardening ratios (SHR) greater than 1. The blends are effective in blown film processing. Also disclosed are related methods for improving extensional flow processability using the branched hydrocarbon comb polymers, as well as the branched hydrocarbon comb polymers themselves, including as a property enhancing additive for such substantially linear polymers.