I would not use Bury Flex 9914 because it has a foam dielectric with a low melting temperature. I would not use LMR600 because (have you actually USED this stuff, before?) it is .600" diameter, very large, very stiff, cannot be bent around a corner, seems ridiculous for a mobile installation.
I'd recommend "direct burial" RG213/U, which has a solid polyethylene dielectric and a much higher melting point; or, if you want something smaller diameter but nearly indestructible with an exceptionally high temperature rating (not to mention power rating, even under mismatch conditions), try mil-spec RG400/U. This is Teflon dielectric cable, rated to 200 degrees C, so it can be run nearly anywhere in a vehicle without concern for deforming, aging or melting. It's also readily available from any industrial cable supplier.
I prefer the Teflon cable because it's so strong and impervious to practically everything. It can be operated underwater, even boiling water, indefinitely and there's no chance of it absorbing water. RG400/U also has two silver-plated copper braids and is 100% shielded. And, best of all, it can take ordinary PL259 UHF connectors with the standard UG175/U reducers, making installation a breeze.
73 de Steve, WB2WIK/6