Just got these heads in on a trade and trying to determine what year they were built. On the underside of one is 08118 and the other has 08308... is this the date code of August,11 1968 and August 30, 1968? What would these have been used on from the factory?

Your dates are correct.
Aug 68 would be for 69 production.
3946074...rect...OPEN...'69 427 L88, ZL1, Aluminum, 118cc chamber

fwiw. they work well, ported, but are somewhat pourous.

A lot of them were broken in various places over the years then welded up. If the welder knew what he was doing they are fine.

Those are over the counter heads/service replacement heads.

They were cast in Aug of 1988 I believe. All the heads I have ever seen cast in the 60's and 70's were cast "69" or "79" for the year. If they were 1968 it would read 8.11.68.

Here is a picture of my 842 heads cast in Aug of 1968.

http://i300.photobucket.com/albums/nn2/brkyard/Parts/COPO-CleanedHeadsCastingDate-1.jpg

Kurt

I agree with Kurt that those are later OTC service replacements and that style casting date is NOT for `68.
I see these come up for sale, with guys trying to pass off that style casting date as 68, many times before.

I have a set of 074 heads that are dated 9.18.73 & 11.16.73.

That is why I don't believe they are 1978 heads. Otherwise they would be dated 78 for the year.

It's the same thing for the 3933163 intakes we see for sale all the time.

Basically they are open chamber aluminum heads that will breath a lot better than a set of closed chamber heads. They are the same thing I am contemplating using on my car. From what I understand it is best to have heli coils installed to keep the studs from pulling out. I have even heard to have the exhaust threads double heli coiled and install longer bolts.

I have a email from a guy in NY who explained this to me last year.

Kurt

Missed a digit ,sorry.

^^^^^ What they said, here is a pic of one of my 074 dates.

http://img.photobucket.com/albums/v604/rodent4/Picture-155.jpg

I have a set of 074 heads that are dated 9.18.73 & 11.16.73.

That is why I don't believe they are 1978 heads. Otherwise they would be dated 78 for the year.

It's the same thing for the 3933163 intakes we see for sale all the time.

Basically they are open chamber aluminum heads that will breath a lot better than a set of closed chamber heads. They are the same thing I am contemplating using on my car. From what I understand it is best to have heli coils installed to keep the studs from pulling out. I have even heard to have the exhaust threads double heli coiled and install longer bolts.

I have a email from a guy in NY who explained this to me last year.

Kurt

Be very carefull when drilling for double herlicoils in the exhaust studs..the center ones near the heat crossover are shallow and you can drill into the wall separating the heat crossover and the water jacket that is underneath the stud allowing water into the heat crosover and under your carb!!..very expensive fix too..ask me how I know !:clonk:

Al, the info I got was from Gary (GOFAST). He was very helpful with some questions I had. I am actually thinking of sending mine out to him if I can't find anyone close to me that can do my 074's the correct way.

Here are some pics of the casting dates..http://im1.shutterfly.com/media/47b9cc27b3127ccef89901e6f4a500000030O00AYuGTFi2ZuW IPbz4M/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/
http://im1.shutterfly.com/media/47b9cc27b3127ccef8998b8075b600000030O00AYuGTFi2ZuW IPbz4M/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/

Roger, those are definitely OTC heads. There is nothing wrong with them but they are not from 1968. I am surprised someone with more knowledge than me has not chimed in and said the exact year they were cast.

Kurt :beers:

Roger,

I am 99 percent sure those are over the counter heads/service replacement heads. As stated previously the last 8 is for 1978 or 1988.

I have a pair of the same casting number. I can't remember right off hand but I think one is dated 70 and the other 71.

Roger, those are definitely OTC heads. There is nothing wrong with them but they are not from 1968. I am surprised someone with more knowledge than me has not chimed in and said the exact year they were cast.

Kurt :beers:
Kurt, i had just assumed that they were cast in 1968 as i didnt think i had ever seen a set of these heads that were cast as late as 1978 and i REALLY would not have considered 1988. Was the Winters foundry still casting these heads as late as 1988? and if so did the metallurgy improve in the 20 years of casting these heads?

For more detailed information on the heads, I would PM Gary (GOFAST).

Yes they would have the winters logo. Mine have been ground down and smoothed out. :sad:

Here are a couple of pictures of my 074 Heads.

http://i300.photobucket.com/albums/nn2/brkyard/1969%20Chevelle/100_2370.jpg

http://i300.photobucket.com/albums/nn2/brkyard/1969%20Chevelle/100_2374.jpg

http://i300.photobucket.com/albums/nn2/brkyard/1969%20Chevelle/100_2378.jpg

http://i300.photobucket.com/albums/nn2/brkyard/1969%20Chevelle/100_2377.jpg

Hi, i dont believe the 074s were cast past 1974 or 1975 but i may be wrong.

I have set i want to replace which has a large sum of money invested between the heads, porting and mods, only to find out they never got zyglo tested or something and found several cracks almost 2 years after getting them back and never being used! They sat on shelf put some springs on them a few months later took them from shelf and cracks galore!! Not good.
Anyway i would be very carefull using these castings, poor quality aluminum, gets worse with age, very soft, plus notorious for dropping seats and cracking!!
The only reason i am running them is they are requierd by class rules for my zl camaro clone for Supercar and FAST competetion.

Ryan
here is a link to my camaro build and the sites..
http://www.supercarraces.com/phpBB3/viewtopic.php?f=5&t=476

www.supercarraces.com (http://www.supercarraces.com)
www.fastraces.org (http://www.fastraces.org)

fwiw. they work well, ported, but are somewhat pourous.

Gene

You have a PM

Ray

Here is a perfect example of OTC 3919842 heads that were made in the 70's or 80's.

If you look them up on Mortec.com they say "3919842....68-69...rect..CLOSED..396, 427, Aluminum L88, L89, 107cc chamber".

This is very deceiving because the dates end in a "9" so someone might think they are for a '69 and they're NOT.

I don't know how to decipher the casting date other than Nov. 31st but the year is a mystery to me and that might not be correct either.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=190363756420&viewitem=&sspagename=ADME%3AB%3ASS%3AUS%3A1123

http://i300.photobucket.com/albums/nn2/brkyard/Parts/BjDcwtwBWkKGrHqUH-D0Es-YhG0HyBLR682.jpg

Another set of OTC heads for sale on eBay that are being sold as 1968 castings. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=150408062920&viewitem=&sspagename=ADME%3AB%3ASS%3AUS%3A1123

Here is the description:

You are bidding on a part of GM Aluminum Heads, part # 3946074. These heads appears to be ready to bolt on, but please check them before using. One head have 2 repaired bosses (see pictures) that appears to be done professional. The other head have 4 heli coil repair (see pictures). The dates are 8/11/68 and 8/30/68. I prefer paypal or cashiers check. Payment is required no later than 7 days after auction ends. Please email me with any questions.

http://i300.photobucket.com/albums/nn2/brkyard/Stuff/BkQq-LgWkKGrHqYH-EQEt7T87LIBLW1pVPi.jpg

http://i300.photobucket.com/albums/nn2/brkyard/Stuff/BkQq76wBGkKGrHqYH-DgEtHzoJtBLW1pOh6.jpg

Like you're saying Kurt, those are `78 or `88 date codes when they don't have a (.) DOT between the numbers.
Here's a set of 1970 dated 074's

6.17.70
http://i36.photobucket.com/albums/e43/Rixls6/032.jpg
6.11.70
http://i36.photobucket.com/albums/e43/Rixls6/030.jpg