If your "custom" rig can handle high temp oil, and you're draining it into a standard gas can, then this Liquivac can definitely take the heat, as it's made from the same materials, it's just a lot thicker than the standard gas can. maybe the manufacturer's warning about heat is just a disclaimer?
"We drive into the future using only our rearview mirror."
- Marshall McLuhan -
Northern California Wine Country...
"Turbos whistle, grapes wine..."