Vented Gas Cap for '72 Tank

[crakarjax]

I put a clean '72 tank in my '68 and got rid of the emissions stuff. Now I need to find a vented cap but it is proving to be quite elusive! The typical 68-70 vented caps (stant 10623) are too large to fit on the '72 filler neck. The '71 caps (stant 10704) look like the earlier caps in some pics, and look like the '72 caps in others; not sure what's going on there.

I was able to find on autozone's website what looks to be a vented cap but might be a typo: part link

Does anyone know what the right cap is?

[LockDoc]

If you haven't already check with NAPA.

LockDoc

[SOON2BLAZE]

funny this came up as I just replaced mine yesterday on the blazer. Orielys even had it in stock. let me know if you need the part #

[Critter]

I got one from Autozone a few years ago for my 72 Blazer. Only cost a few bucks ($6 maybe...) but it quickly rusted through the chrome. If I had paid anymore for it I would have been upset.

[SOON2BLAZE]

Murry Ultra 6742 is the one I ended up with. No knurled edges on the side of the cap. $7.00

[69sixpackbee]

Drill a small hole in it. Done.

[crakarjax]

Originally Posted by SOON2BLAZE

funny this came up as I just replaced mine yesterday on the blazer. Orielys even had it in stock. let me know if you need the part #

I'm seeing 6742 as the part # for a '72 blazer on teh oreily website but...

Originally Posted by SOON2BLAZE

Murry Ultra 6742 is the one I ended up with. No knurled edges on the side of the cap. $7.00

That cap is not vented, it's the stock '72 cap which means it is not vented... or is it? The oreillys website does not say, although the stant 10742 is not vented so I assume this one also is not vented?

Drilling a small hole isn't sounding all that crazy actually...

EDIT:
That oreilly/murray cap is the same exact stock picture as the autzone cap I linked to in the first post... can anyone verify that the cap is indeed vented?

EDIT2:
How do you visually check to see if it is vented?

[crakarjax]

I think I determined that the up to '71 and 3/4 ton caps are larger diameter, so the '71 cap I was looking at will not work. Also, the first set of dog-ears is too shallow on that cap.

And the Gates website says this about their *742 cap:
Part # 31742

Application
Features Advantages Caps also fit vented, non-vented and vented anti-surge.
Caps fit both shallow and deep cam filler necks.
Rugged, heavy-duty construction. Meet or exceed OEM specifications.
Three configurations available for most popular applications.

Venting Emissions Control


So, it FITS both vented and non-vented but it can't WORK with both, right?

[crakarjax]

I guess I should update:

I bought the stock '72 stant cap. It IS vented, but I think it is only one-way: it lets air in preventing a collapsed tank but won't let gas fumes vent into the atmosphere. I am not too worries about my tank blowing up from pressure buildup... I'll check it on a couple of hot days to see what kind of pressure builds.

The new stant cap looks cheaper than the older ones also... no ribbed sides, a less polished look... might be stainless steel though, I can't really tell. That, or really crappy chrome.