May I suggest Times Wire LMR-400. It has lower loss than RG-8 or 213, and is usable to well over 450 mHz. It's pretty flexible, too. Diameter is same as RG-213. Type N and UHF connectors are available.
Belden 9913 has about the same or slightly higher loss than LMR-400, and is easily damaged.
When you buy LMR-400 in 500' spools, it can cost less than RG-213. If you can't find it at a ham dealer, check out www.tessco.com