66 Valve covers

[John C.]

I need an opinion:

Do all 66's 427, build date Dec 8th 1965, need to have a dent in the right side valve cover.

Are 67 big block valve covers the same as the 66 BB covers?

Is the aluminium intake manifold painted silver? If not, why did they paint the thermostat silver? Which intake bolts should I use and what finish.... Thanks.

[Michael H.]

Re: 66 Valve covers

I need an opinion:

Do all 66's 427, build date Dec 8th 1965, need to have a dent in the right side valve cover.

Are 67 big block valve covers the same as the 66 BB covers?

Is the aluminium intake manifold painted silver? If not, why did they paint the thermostat silver? Which intake bolts should I use and what finish.... Thanks.

John,

Because you mentioned an aluminum intake manifold, we know that you are working on a 425 HP and not a 390 HP.

For the 66 model year, only the 390 HP engines had the dent in the right/passenger side valve cover. The depression was needed for clearance for air conditioning, if so equipped.

I think the difference between a 66 and 67 valve cover would be the left side cover. For 67, a spark plug wire support was added to the inner rear corner of the cover.
I can't think of any differences between 66 ad 67 right side covers for solid lifter engines.

I don't think dull aluminum paint was used on the intake manifold or the thermostat housing. The housing was/is aluminum.

[John C.]

Re: 66 Valve covers

Michael
Thanks for the info,the JM is a little unclear.

[Ronald L.]

Re: 66 Valve covers - 390HP early vs mid year

I am seeing sources for valve covers, again 1966 427 390HP option that show significant differences pre FEB 66 versus later - any one out there than can lend insight as to what is very correct?

[Steven S.]

Re: 66 Valve covers

For the 66 model year, only the 390 HP engines had the dent in the right/passenger side valve cover. The depression was needed for clearance for air conditioning, if so equipped.

Thats it, depression for AC hardware up to sometime mid model year, then it disappeared.

Steve

[Ronald L.]

Re: 66 Valve covers

Thanks - I have seen this and thus my dilema. One parts supplier quotes Feb 66 as the cut over, others show nothing (no dilema there).

My dilema is I have a late April motor with the dent on the cover and this motor has been un touched since 1975 we know for sure. Question is will this be a problem for judging?

[Mike B.]

Re: 66 Valve covers

John and Ronald,

If you've got a copy of Noland Adams Restoration and Technical Guide Vol. II, you can see under the '66 AC section pg. 338 some great shots of the dimpled valve cover on an L36 with AC and one without AC.

Again, under the description of the L36 engine pg. 351 he shows a non AC L36 with the dimpled cover and a great explanation of what we're discussing here on pg. 353. He says the dimpled VC had no indentations at all-at first. Then due to suspected interference with the compressor bracket, a large dimple was added. He states that this VC was installed on L36 and L72 engines, whether they had AC or not.

He further states that the bracket caused no interference and the dimple was eventually removed. He says the changeover period was as follows: Initially there was no dimple, then around mid-November '65 it began appearing along with smooth covers through mid-May '66.

Ronald, your car fits nicely in there. Sounds OK to me anyway. My L36 w/AC was assembled late Nov. '65. "Bubba" had robbed the covers from the engine back in the 70s and I paid dearly to purchase the dimpled valve cover back in the late '80s.

Take care,
Mike

[Lynn H.]

Re: 66 Valve covers

Thanks - I have seen this and thus my dilema. One parts supplier quotes Feb 66 as the cut over, others show nothing (no dilema there).

My dilema is I have a late April motor with the dent on the cover and this motor has been un touched since 1975 we know for sure. Question is will this be a problem for judging?

In one of my many books I have, one goes into the big block valve covers in great detail, with reference to Noland Adams books as well as some other references including:
David Cranes- "Crane Corvettes Guide to Big Block Valve Covers" 1990
"Corvette Fever" articles by G. Pernula (13(12):38-39)
And Wayne Scraba's article in the Oct 91 issue of Musclecar Classics-pgs 52-55
The Book is "1969 Stingray Guidebook" by Rick Bizzoco, and goes into a little more detail concerning change over dates of the particular big block valve covers (it says 5 different total). I know this book is available from Cranes' as well as some other companies.
Lynn

[Ronald L.]

Re: 66 Valve covers

Mike - thank you,

This is the second time on these bases, the first time out was my first 66 427 390, a Dec 13 build car that I did a body of resto on - back exactly 30 years ago.

I remember the discussions back then about the early car having the suspected interference and the dimple being quickly implemented. That car had the same experience as yours and not only did I pay dearly for an original one that year, I ended up getting a second that until last year I had stored (I provided it to a friend in Florida doing a 66 restoration). As I'm cleaning things up, I saw so many variants of things for sale with such defined dates that it is crazy. Crane's has one thing, Long Island another and Paragon yet another.

All in all I did not want to polish the top side of this engine compartment this winter and end up mid summer to find a bad news surprise.

Thanks again.