Here is good test of the PVC system to see if you even need to remove the breather box. Do this with the engine off and cool. Get a two-foot length of 5/8 ID hose. (If you buy PVC hose, you can use it later, in conjunction with a three-inch section of 5/8 OD copper pipe from a plumbing store or building site, to relocate the flame trap if you want.) Pull the flame trap assembly off the breather box, and push the new hose over the nipple on the breather box. Take off the oil filler cap, and try to blow by mouth through the hose that you just connected to the breather box. With a new or super clean breather box, you'll be able to easily blow through it. The easier you can blow through it, the easier your crankcase will breathe. Your breath will come out the oil filler cap hole in the valve cover. This test just checks the breather box. Also, check all the hoses and fittings downstream (above) the breather box, and clean or replace any part that is sludged up or clogged. This includes the brass fitting in the manifold where the little hose connects.

Often people fail to check the breather box when inspecting the PCV system. If it's clogged, a new flame trap with attached hoses and fittings won't do any good. My breather box was totally clogged so I replaced it, although some people do clean the dirty old boxes out. On my 1981 K-Jet, I took off the manifold and the starter, and moved the fuel distributor to access the breather box which had an old metal flame trap stuffed in the nipple sideways. No passage of air whatsoever. Whatever you do, let it breathe. Good luck.
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Thanks to everyone for the help, Doug C. 81 242 Brick Off Blocks, stock, M46; 86 240, 133k