These
plates are those we have removed from cylinder heads they
have undergone no operational tests. You may need to
surface the bottom to make them perfect but a gasket or
some form-a-gasket usually does the trick. The front
small vent pipe is still intact. Make sure you use as
flexible as possible rubber tube. I've seen out of tune
engines jerk these hoses 2 inches left and right. No
piece of brass is designed for repeated bending
forces.
The
area where the cap rides "feels" normal but that and the
cap "hooks" sometimes have to be meticiously, gently
tweaked for best seal. If that is the only problem you
can also consider buying one of the friendly price 3-hole
plates; cutting off the cap stand and having it brazed on
to your 4-plate lid.