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Hi everyone. What year did the Corvette valve covers change their staggered mounting holes to ones directly across from each other?? Was '59 the last year for the staggered mounting holes?? Thanks, Carmine.
 

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Carmine , I was guessing 58 or 59 so I looked it up.... 1959 is correct . Also there is a set of billet adapters to convert 1960 and up vc's to older heads. Just another tid bit of info....there were 9 fins on the early Corvette covers vrs. 7 on most 327's. Last I checked they were hovering around the $400 range.
 

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The 9-fin covers were used for all of 56 and early 57 up to about Dec 56. They had LOW script and the staggered bolt pattern.
LOW script 7-fin covers were introduced after Dec 56 through 58 and had the staggered bolt pattern. HIGH scrip covers with a staggered bolt pattern were introduced sometime in 59 and were used up through LATE 59 when new heads with a straight across bolt pattern were introduced. Service replacement staggered covers had the high script. From LATE 59 through 67, ALL covers were 7-fin with a straight across bolt pattern. Sometime in mid to late 66, the mold for the covers developed a crack which went right through the o in Corvette. Thus, late 66 through 67 covers are correct with the crack (parting line through the o) and all service replacement covers had the line through the o.
The 1968 ONLY optional 327 Corvette engines got CHROME, NOT, repeat, NOT finned alum covers. The new style finned alum covers-------------with FULL LENGTH fins, were introduced in the 69 model year and were used on optional Corvette 350 engines as well as 68-72 Z-28 engines. After 72, there were later versions of the full fin covers, but the 69-72 versions were the "good" ones.

For many years, Chev parts dept sold 7-fin staggered, 7-fin straight across and full fin covers at the same time. While they were still available, they were about $25-30ea. Unfortunately, it never occurred to me to stock up on them. I only bought a few-------------DAMN!!!!!!! I also wish I had stocked up on 2 1/2in Ram Horn exhaust manifolds-----------for about $50ea!
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I can post pictures if anyone needs to see the differences.
 

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Valve covers

They are known for an instant 10hp power bump as soon as you put them on. :sign0020:

Dangerous Joe :viking:
 

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Discussion Starter #6
They are known for an instant 10hp power bump as soon as you put them on. :sign0020:

Dangerous Joe :viking:
Thanks Tom, but I'm good. I understand it.

Joe, with that little 265 bored .030 over, I need all the help I can get :), Carmine.
 

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The 9-fin covers were used for all of 56 and early 57 up to about Dec 56. They had LOW script and the staggered bolt pattern.
LOW script 7-fin covers were introduced after Dec 56 through 58 and had the staggered bolt pattern. HIGH scrip covers with a staggered bolt pattern were introduced sometime in 59 and were used up through LATE 59 when new heads with a straight across bolt pattern were introduced. Service replacement staggered covers had the high script. From LATE 59 through 67, ALL covers were 7-fin with a straight across bolt pattern. Sometime in mid to late 66, the mold for the covers developed a crack which went right through the o in Corvette. Thus, late 66 through 67 covers are correct with the crack (parting line through the o) and all service replacement covers had the line through the o.
The 1968 ONLY optional 327 Corvette engines got CHROME, NOT, repeat, NOT finned alum covers. The new style finned alum covers-------------with FULL LENGTH fins, were introduced in the 69 model year and were used on optional Corvette 350 engines as well as 68-72 Z-28 engines. After 72, there were later versions of the full fin covers, but the 69-72 versions were the "good" ones.

For many years, Chev parts dept sold 7-fin staggered, 7-fin straight across and full fin covers at the same time. While they were still available, they were about $25-30ea. Unfortunately, it never occurred to me to stock up on them. I only bought a few-------------DAMN!!!!!!! I also wish I had stocked up on 2 1/2in Ram Horn exhaust manifolds-----------for about $50ea!
.
I can post pictures if anyone needs to see the differences.
Tom: the '68 Z28's used the same (or similar?) chrome stamped steel valve covers as the '68 Corvette 327/350 engines used... The finned aluminum valve covers began with the '69 Z28 models (and 350 hp Corvette engines). For late production '69 Z28s and Corvettes got the '70 aluminum valve covers (which had drippers)...
 

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Tom: the '68 Z28's used the same (or similar?) chrome stamped steel valve covers as the '68 Corvette 327/350 engines used... The finned aluminum valve covers began with the '69 Z28 models (and 350 hp Corvette engines). For late production '69 Z28s and Corvettes got the '70 aluminum valve covers (which had drippers)...
Yep, I thought that was basically what I said, except I did not mention that 69 Z28 engines got the same chrome valve cover as the optional 68 Corvette SB.
As far as I have observed, ALLLLLLLLLLLLLLL full length finned alum covers got the drippers.
Just how much benefit did the drippers provide?????????? I'm not sure so much, BUUUUUUUUUT, they certainly could not hurt anything. Remember, beginning in 57, the hi-perf solid lifter engines up through 68 DID NOT have drippers and they did just fine without them! Personally, I like the drippers.
 

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Yep, I thought that was basically what I said, except I did not mention that 68 Z28 engines got the same chrome valve cover as the optional 68 Corvette SB.
As far as I have observed, ALLLLLLLLLLLLLLL full length finned alum covers got the drippers.
Just how much benefit did the drippers provide?????????? I'm not sure so much, BUUUUUUUUUT, they certainly could not hurt anything. Remember, beginning in 57, the hi-perf solid lifter engines up through 68 DID NOT have drippers and they did just fine without them! Personally, I like the drippers.
I'm not sure if these are the full length finned covers you are talking about but here is a set without drippers. They do appear to be original GM parts.

https://www.ebay.com/itm/1969-Chevrolet-Camaro-Z-28-302-VALVE-COVER-PAIR-ORIGINAL-GM-3932418/143349013232?epid=656061950&hash=item2160445af0:g:BHQAAOSw6RRdShhc&LH_ItemCondition=4
 

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Yep, I thought that was basically what I said, except I did not mention that 68 Z28 engines got the same chrome valve cover as the optional 68 Corvette SB.
As far as I have observed, ALLLLLLLLLLLLLLL full length finned alum covers got the drippers.
Just how much benefit did the drippers provide?????????? I'm not sure so much, BUUUUUUUUUT, they certainly could not hurt anything. Remember, beginning in 57, the hi-perf solid lifter engines up through 68 DID NOT have drippers and they did just fine without them! Personally, I like the drippers.
The statement that was incorrect was this one... "The new style finned alum covers-------------with FULL LENGTH fins, were introduced in the 69 model year and were used on optional Corvette 350 engines as well as 68-72 Z-28 engines.'

PS. I like the drippers also, as they make sure the rockers/balls have oil...
 

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I'm not sure if these are the full length finned covers you are talking about but here is a set without drippers. They do appear to be original GM parts.

https://www.ebay.com/itm/1969-Chevrolet-Camaro-Z-28-302-VALVE-COVER-PAIR-ORIGINAL-GM-3932418/143349013232?epid=656061950&hash=item2160445af0:g:BHQAAOSw6RRdShhc&LH_ItemCondition=4
Yes, those are the valve covers used on 350/350 Corvette engines and the 302 Z28 engines for *most* of the 1969 model year. Both those models (Camaro and Corvette) were extended production in 1969, and the last few months of the production used the 1970 parts (with drippers)...
 

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I'm not sure if these are the full length finned covers you are talking about but here is a set without drippers. They do appear to be original GM parts.

https://www.ebay.com/itm/1969-Chevrolet-Camaro-Z-28-302-VALVE-COVER-PAIR-ORIGINAL-GM-3932418/143349013232?epid=656061950&hash=item2160445af0:g:BHQAAOSw6RRdShhc&LH_ItemCondition=4
Yes, those are original GM full length finned covers for Corvettes and Z28s. If you look closely at the picture of the underside, you can see where the drippers were remove by someone. I've never seen any that were made without drippers.
 

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The statement that was incorrect was this one... "The new style finned alum covers-------------with FULL LENGTH fins, were introduced in the 69 model year and were used on optional Corvette 350 engines as well as 68-72 Z-28 engines.'

PS. I like the drippers also, as they make sure the rockers/balls have oil...
You are EXACTLY correct. I went back and edited it from 68 to 69. I must have accidently hit the 8 instead of the 9, because I knew that optional 68 Corvette small blocks and 67-68 Z28 302 engines got chrome covers.
 

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Yes, those are original GM full length finned covers for Corvettes and Z28s. If you look closely at the picture of the underside, you can see where the drippers were remove by someone. I've never seen any that were made without drippers.
Tom, I don't think the drippers were removed on that valve cover. The part number is correct for the 'first '69 finned VCs (without drippers - 3932417 & 18). See first photo...

The finned VC's were subjected to a minor redesign for the 1970 model year incorporating the drippers; the '70 and later VC's had totally different PN's (3965543 & 44). see second photo.

Since '69 Z28/Corvette production was extended for a few months into what was normally the 1970 model year, the ' very late' extended production 69 VC's had both early/late numbers cast in (see third photo) and these were the first VC's with the drippers.

note: The LH and RH VC's are the same casting, but are finished differently as only one side has the 'punch out' for the oil fill.

PS. I only know this because I have original late production 69 Z28/RS and '69 Corvette (350/350 engine) and they both have the late '69 dripper Valve Covers, and this has been a 'contentious' point in judging original restored '69 Z28's...
 

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Discussion Starter #15
My search for a set of Corvette valve covers is over. Went to visit a friend and he gave me set off his '66 327 that he had for years. I'm going to clean them up and use them on my engine. I'm glad that is over with, Carmine.
 

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Carmine, The valve covers from a '66 engine will not work on 1957 heads!
 

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If I remember correctly, Carmine also has a set of '64 327/250 heads stashed away :)
 

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Carmine, The valve covers from a '66 engine will not work on 1957 heads!
Just for the sake of stimulating some curiosity, here is a 9-fin, staggered bolt pattern valve cover bolted to a 1966 462 head, which is on the fuel injected SB400 in my 56 Vette..
Oh ya, and no adapter was used.
 

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Discussion Starter #20
Just for the sake of stimulating some curiosity, here is a 9-fin, staggered bolt pattern valve cover bolted to a 1966 462 head, which is on the fuel injected SB400 in my 56 Vette..
Oh ya, and no adapter was used.
They look real nice. Did you re-drill the head itself to accommodate the staggered pattern?? I didn't think there was enough head material to do that, Carmine.
 
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