What kind of gas cap should I use?

[The Swed]

Here's a picture of my tank and the catalog states that it's an EEC (Evaporative Emission Control) tank. So my question is do I need a vented cap or non vented cap?

Thanks

[Lattimer]

Doesn't look like an EEC tank to me, but could be the photo.

EEC tanks have a vent port on the filler neck, and I don't see one there.

If you are using the EEC system, you can use a non vented cap. if you don't have EEC or have plugged it off, you will want a vented cap.

[michael bustamante]

. i have a new old stock gm gas cap for sale if you need it.

[The Swed]

Here's a picture of the catalog. Hard to tell if the picture has a vent port on the filler neck but I know my tank doesn't. Well now that I enlarged the photo I see the tube... getting old sucks. I thought the ridges on the neck vs a smooth neck was the criteria.

Thanks Lattimer

[GASoline71]

Doesn't look like an EEC tank to me. Here is a couple of pics of my EEC tank in my 1972 GMC.

Non EEC tank... run a vented cap. EEC tank... run a non-vented cap. Or like me... have an EEC tank without the EEC hooked up... run a vented cap.

Gary

[The Swed]

I see said the blind man! I got it now. No EEC in my truck.

Thanks

[GASoline71]

You betcha!

Gary

[SS Tim]

The ribbed filler is the "safety filler" a deformable design independent of the EEC. 70 EEC usage was California emission only, 6000lb GVW and below (CK10).