Open vs. Closed Valve cover breather

[Schloss3@aol.com]

Does anyone know when the TR4 switched from an open breather cap on the valve
cover to the closed setup with the fumes being routed to the air cleaners?  I
have three valve covers for my car and all three have the tube to use for the
closed breathing.  The car is a 61 and one of the former owners might have
swithed over.  If I decide to keep this setup, can I use the SU carbs, or do
I need to use Stromberg.  I have both so I have my choice.

Paul
61 TR4