In non-turbo 850s, it's located in a housing in the large air intake hose (between throttle body and MAF meter) just in front of the throttle body and towards the firewall side. It has two hoses going to it, one's a vacuum hose and the other's a larger PCV hose that goes to the breather box under the intake manifold (just like your 740).
If the flame trap is clogged and/or any of those hoses, you'll have excessive blowby.
I've seen several older 850s where this has been ignored previously and oil was blowing from everywhere (even oil fill cap with a new seal) and once the PCV system was repaired, the engine was dry as a bone afterwords.

If the flame trap housing is eroded away and/or you're unable to remove the old flame trap, get another housing as they're only a few bucks. Make sure that the vacuum supply (hose and vacuum T nipple) is good and that the PCV hose to breather box (including breather box) is also not clogged (blow through it).