New AC Oil Fill Cap - Aluminum Valve Cover

Anyone know if this oil cap will fit the aluminum factory valve cover. Visually it looks very close to original on the top side.
http://www.ebay.com/itm/68-79-Ponti...m2c65c6c1c1:m:mupqUdBTfNELxDbNR1jgGhg&vxp=mtr

Thanks

 

I was also looking at a cap like that but wondered if it needs to be vented?

 

thats what i'm thinking. but the stock original oil cap was a breather type cap, plus opposite valve cover had a pcv valve.

 

Jason, I think that's it, not sure tho.
'66 parts book says it's group 1.762 pn 6410204
Also used 69-73 Stage 1 (chrome)

There's another pn, 6410394, listed for 70-74 455 (Stage 1).
That should be chrome too?

One of them is the AC-FC65. Lots of posts here for that #. Here's a good one:
http://www.v8buick.com/showthread.php?195342-AC-Oil-Fill-Cap-quot-FC-65-quot

Note Dave's comment they were also used on '84 Century with v6.

 

Some valve covers, like the '66 aluminum ones, had a chrome breather at the front and a chrome oil filler cap in the center.

 

Thanks Walt! That part number info gives me a little more confidence.
The ebay listing defers questions on applications to Inline Tube which is the supplier. I called Inline but they could not answer.
I sent a question off to the seller asking if they could take measurements of the gasket and locking feature. I doubt they will but as incentive I explained if it is a match it will expand their application listing.

Was going to get my original replated but its a little pitted and the letters would probably get wiped out in the prep process.

 

Did some more research in a 1985 AC-Delco catalog.

They list two caps for '66 with alum valve cover, FC-2 and FC-91.
Those numbers are also used in Buicks into the 1980's, including 70-73 455's.
The chrome version is FC-65.

Pontiac listings for 68-74 and 75-81 is also FC-2 or FC-91.
Other caps listed are FC-67 for 73-75 Firebird Hi Perf, and FC-60 for 78-81.

I couldn't find the smooth-top cap you are looking at anywhere else. If it fits the listed Pontiacs, it should fit our 66's too.

The '70 GS guys were discussing the chrome FC-65, which has a rivet in the center:
http://www.ebay.com/itm/70-79-Trans...m2ec2a78d6d:m:mAbQ2pcu2oxlv-pUeAhrK0w&vxp=mtr

The riveted cap vs non-rivet may be the difference between the two GM pn's I mentioned earlier.

 

Received this cap today. Your research was right on Walt. :TU: Fits perfect and looks like original.

For when the ebay link disappears it is Part Number INL11060 from Inline Tube.

 

That is correct. My '66 aluminum covers are exactly like that. The PCV system has to get air from somewhere to replace the air that it removes from the crankcase. In the early years of PCV, most manufacturers used an "open" system where the air intake was through a vented oil filler cap or separate breather. Later systems usually ran a hose from the air filter to provide clean air to the system.

 

Thanks for the review Jason!
Now that you verified their 'correctnes', I'll have to pick some of these up.

I take it these have the 2 pieces spot welded together. The later ones are riveted. Wonder if that change was done for durability or for cost savings.

 

Walt,
Looking at the pic you can 3 see witness dots around the AC stamp presumably from the spot welds. The one I received looks just like pic. The only difference I could see is the AC font is a little tighter/narrower and its rotated 90 degrees relative to the position of the ears. I don't know if all originals were stamped with same orientation or not. I'm picky but fine with that minor difference. Just wanted to point it out. When its installed and locked in position the ears are pointed the same direction as my original (angled about 45 deg from the fins)so its correct in that aspect