If simply replacing the road draft tube with a freeze plug and a grommet would work, why would the GM engineers go to the trouble to build a standpipe with baffles in it, and place the valve high above the crankcase? The entire idea of putting the PCV valve down where it can pick up oil splashed off the crankshaft is ludicrous. Even though there's a sheet metal splash shield inside the block, it cannot do an adequate job of preventing liquid oil from being sucked up by the manifold vacuum. The freeze plug and grommet setup is an ill-conceived Rube Goldberg approach to crankcase ventilation which cannot be successful. If you don't have access to an original PCV setup, it's pretty simple to cut the road draft tube off, weld a threaded bung into the canister, and position the valve high enough to let gravity keep oil from being sucked up and burned. It can be done with various off the shelf components from any hardware store. There are also several varieties of PCV valves with different flow volume, depending on engine size, that won't cause excessive vacuum loss and poor windshield wiper performance. Try a PCV designed for a 200 cubic inch engine or something similar- - - - -maybe a Ford 200 6 cylinder, or maybe the old 170 engine used in an early Falcon.
Jerry
