Hi All,
Here is a discrepancy that has been nagging on me for a while.
I have 2 140s a 69 142s (now a parts car) a 70 145, both with B20s and a webber carb kit.
The PCV hose runs from the air cleaner to the oil cap, then from the oil trap on the side of the engine block to the vacuum inlet on the intake manifolds.

Referencing the Haynes manual, is say the B18s where set up that way, with the flame trap in the oil cap. But the B20s are reversed with the hose going from the air filter though a flame trap to the oil trap on the side of the block, then from the oil cap to the up to the air filter. This is close to how it was in my 84 240.

Now, unlike my old 240, the oil trap has no flame trap on it. So if I route the hoses acording to the haynes manual I run the risk of a backfire through the carb igniting fumes in the crankase, which I asume would the bad.
The oil filler cap looks like its big enough to house a flame trap and a small family of marmosettes.
The Haynes is a British publication, so did they only do that in Europe and route the b20 US cars like the b18? or am I missing a flame trap over my oil trap?
Is there an alternative, like a vented oil cap and a small air filter to put on the oil trap?