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RIP (12/27/60-7/18/15)
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Discussion Starter #1 (Edited)
What are the "extra" 2 holes (in the lower front outside edges) of the timing chain cover for?
Also, what are the 2 holes in the front of both heads?
The non- threaded ones
thanks as always
(pours GTO guy another 1800 shot)
:)
 

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The holes in the timing cover are "leftovers" from days past. The early V8 cars ('55-'59, anyway, maybe a bit later) use a "front mount" where the timing cover was used to support the front engine mount. I have a '57 347 here from a Starchief with the mount still attached. All the early stuff had a cast iron cover. They MAY have used the aluminum version in the '62-'66 GMCs, can't say for sure.

Which holes in the heads? You mean the 1 3/8" diameter? They're for expansion plugs, and the only "non-threaded" holes in any of the cores here now. If not, what casting number, and a more precise location on those holes?

Jim
 

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the ones to the outside
Ah... those heads are 670's right? Those are the fittings where the A.I.R. (smog pump) connected, if the car originally had one. Looks like yours are open. You'll probably want to find some pipe plugs to seal those holes off on both ends of the heads, if they're open.

Bear
 

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RIP (12/27/60-7/18/15)
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767 Posts
Discussion Starter #6
my car does have the AIR system , as it was made in CA, this being said, what goes in the holes?
ty
 

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There is a cast aluminum piece that bolts over the front of the head that has an outlet for the AIR pump hose. You may be able to find pics of one on line. My car is a Federal car, from Tennessee, so I can't show you a picture. If you don't have all the pieces, good luck. They are almost impossible to find, and command a premium price.
 
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