Won't start

The capped off port on the driver side of the carb should have a hose to the input nipple of the thermo sensor on the underside of your air cleaner body.

You've got the wrong nut on that rearmost exhaust manifold stud. See here. The white stuff is coolant, which means you'll need to remove that too-short stud, install the correct stud with the correct sealant on it, then put everything back together. High probability you need to replace the gasket again, too. It is very much worth your while to get the good gaskets for the manifolds-to-head and intake-to-exhaust junctions.