NO EEC has to have a vented cap, typicaly, from what I hear....
I would think it needs a vented cap also but the parts books say they take a sealed cap and I understand they came from the factory with a sealed cap.I was told by a buddy his NCRS book says it must have a sealed cap.Quanta also says they take a sealed cap.So how does the air get in? I doubt the return line can add air.
ANY car without a EEC charcoal canister type arrangement, HAS to have a VENTED CAP or some such valve to allow airflow in/out of the tank....
I was referring to my '72 wit the black plastic thing that has this seldom seen fault with the sticking ball, allowing pressure in the tank to go positive....noticed to varrying affects when I go fill the tank just off the freeway....overnight, the affect is less....obviously, as the gas cools off....
from what I read above, the parts books are RONG.....that much I remember from many earlier comments over the years....the only cap listed these daze for our tanks is the sealed cap meant for the EEC/canister system....
:gurney:
OH, to vent the caps for use with your car, I would just drill a 1/32 hole in the cap, and tap the edge inside that goes against the center spring loaded piece....tap that edge down a hair in one spot to allow gasses to escape....
NOW, having said that, you maybe get some fumes in your garage from that....
but that's same as any old car....vague gasoline smell....my wife is allergic to it, so it's a sensitive topic with me....had to go to extra lengths for that reason...attached garage....