As per my new intake set up (carbs) my cooling routing is described with the attached (ugly) drawing.
Any risk of problems?

 

you need the loop else the water wont circulate properly when the thermostat is closed.

well, i guess it'll go through the heater core, so you're okay.

 

You'll have no problems removing the lines which formerly fed the throttle body and thermostatic valve on the intake manifold. However, you should cap the port on the lower thermostat housing to which they previously connected, and leave in place the line running between the lower thermostat housing and the small inlet port on the mixing manifold where you currently have the purple "closed" arrow, rather than removing it and replacing it with the green "loop" hose.

Why is this?

Well, that line had two functions originally. It obviously carried the return flow from the intake manifold and throttle body, however it also permitted a small amount of coolant to bleed off of the lower thermostat housing and return directly to the water pump inlet. The purpose of having that bleed may not be obvious, but consider the placement and operation of the thermostat itself.

The thermostat is already seperated from the head by some distance, and is therefore sitting in a pool of otherwise stagnant water. The bleed hose is there to ensure that some water is always flowing past the underside of the thermostat, which is where the wax element that causes it to function is located. In other words, this bleed ensures that the thermostat is always exposed to the same temperature as the rest of the engine.

Were this bleed not in place, the temperature of the water directly surrounding the thermostat would tend to run a bit cooler than the water circulating through the rest of the engine when the thermostat is closed (particularly when the engine is in the initial warmup cycle) which would cause the operation of the thermostat to lag somewhat.

So keep that hose in place.