Datsun Roadster Forum-311s.org

All,
Just an FYI. Went to Weber's and wanted heater functionality. Plumbed the feed and return direct. Feed is the fitting coming out of the head. Return is to the water pump fitting.
1/2 inch heater hose from parts store. Snug fit on the firewall fittings, but works great. Routed under the carbs along the body, away from the exhaust and heat. A few zip ties to keep in place.

May I suggest that you add a heat shield? You could add one and have hard lines attached to the bottom similar to the OEM 1600 setup. I have a custom manifold that I made a heat shield for - I traced a 2000 heat shield and cut it out.

I did a similar heater hose set up as you but ran them under the carbs and haven't had a issue with burning but I did wrap the headers. I made up a heat shield with a layer on top and bottom of heat insulation material I got from Summit (I think) and the hoses run just under that. I found I had to have the heat shield or the carbs would smell of gas after I shut down from the float bowls boiling. Can I ask what jetting you're using? I have a 115 MJ, 160 air jet, F15 emulsion tube and F9-55 idle jet.