Servo convertion

[ggcton]

I was looking at an Amazon at a show recently before reconnecting the servo on my car.
The set up was a hose with a one way valve servo to manifold and a T piece with a pipe to the sump breather.
My question is ,is there a restrictor in the pipe from the breather or does the one way valve in the main pipe do that job of preventing the system being open to the atmosphere.
Thanks

[Volvorama]

Yes, the breather part must have a restrictor.
The original set-up I'm familiar with has two fittings in the manifold; one with a restrictor for the crankcase breather (hole diameter 2 or 3mm) and another straight through for the servo (about 10mm). Sounds like you have the parts to use a single manifold fitting with the restricted branch connected to the breather. If this is the case the existing restricted fitting in the manifold will need to be replaced with a large diameter one.
Incidentally I run a '68 122S estate that had its servo removed in an earlier life. The brakes work qute well but the pedal is very heavy. Before I put a Lockheed servo on I'm going to try some EBC competition brake pads (Green stuff probably). These provide greater friction and may improve the pedal feel. B18 120s with servos are difficult to bleed, very difficult sometimes.