Sorry, a PCV valve is different than a gulp valve. PCV is Positive
Crankcase Ventilation and a PCV valve is used to control the flow of fumes
from the crankcase into the intake manifold. It has to be at least
partially open at cruise conditions.
A gulp valve opens only when manifold vacuum is higher than cruise
conditions. I don't believe they were ever used on TR6s, I
I know they weren't used on TR250s. I believe TR6 used the 'bypass' valve
built into the throttle plates, instead.
Moss' downloadable MGB catalog shows both types of valves.
80 Chevy with both gulp and PCV valves, just passed smog inspection with
flying colors HURRAY !
59 TR3A don't need no stinkin smog inspection