This
part was used on emission controlled cars (USA) on valve
covers that did not have a separate crankcase vent. It can
also be used on covers where the original crankcase vent has
been damaged. You weld up the damaged vent connection so it
doesn't leak and use this cap and stand in place of your old
"flat cap".
Datsun
Roadster Parts from Rallye Enterprises, Ltd.

