Cooling - What’s this small hose?

there was a Tech Serv Bultn that attempted to improve the venting of the coolant.

IMO, not very good ideal

Thx jfb05177, for a really quick answer. 
I wasn't aware of this "update" on 1974 - so good to know. Though I'm not sure I understand the idea. (honestly I'm not good a coolant systems)

Anyway - do you have an idea of what to do with the small hose now? - what can I do?

/Chris

given the new tank does not have a bung for the tube nipple.  leaving the tube off seems to be the answer. 

You MUST find the other end at the radiator and close it off somehow.

My 73 had the radiator banjo fitting hosed to the other "37" connection on the coolant return pipe.  

The new tank doesn't have any bung, only the two big in/outlets and of course the overflow bung in the top. See attached picture. 

Aha, so the small hose goes to the radiator in the front of the car? - I'll have to follow it and find out if there's a banjo fitting that I can close a you suggest. 

Perhaps I can take a picture and attached in a post in few minutes. Working on the car as we speak. :-)

Here’s a picture of my radiator - and it looks like there’s a small hose in the exact same size and looks as the one I removed from the old pressure tank. Here connected to the radiator via a banjo. 
Is this the same way it was done on yours?

(NB: I haven’t followed the hose from the engine room to see if it’s going to the front/radiator)

On my early car (s/n 1744) the small hose on the radiator goes to a fitting on the main radiator connection hose.  It has a small 'T' connection which I have always assumed was for bleeding / filling purposes.  The main pressure tank on my car had a temperature sensor in the middle port - doing what god knows.  I have since plugged that and chucked the sensor.