[TR] tr3 open/closed radiator system

[Frank Fisher]

was at a car show recently and saw a TR3 with one of those overflow tanks off
to the side of the radiator.
not sure if its called a open or closed system.
i
have a nice copper overflow tank from an mgb with a radiator cap on it
available.
so what are the advantages and disadvantages?
will the overflow
have to be higher than the fill neck of the standard radiator. the one i saw
was not.
is their anything special about the installation? just add tubes and
match the psi of the 2 fill caps?

and while we are talking radiators, whats
the thoughts on advantages of a higher pressure radiator? it raises the
boiling point but not the operating temperature.

Frank