Running a proper Heatran check is necessary for any consistent team first off, so I'd try to restructure your team to have one of these. Regardless, if you are deadset on keeping it as is for some reason, try HP Ice for catching some 4x on very common Pokemon, perhaps.
I have a check for Heatran: Gliscor. However, even with heavy investment, its SpD isn't great, so it struggles to take more than a regular magma storm. It can outspeed and force Heatran out with EQ, but if it takes a FF boosted magma storm, it probably won't be able to switch in on it again. I don't think I can replace Gliscor, as I need it to check banded TTar.