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#81
Originality / Re: Early Casting Date on the ...
Last post by bcmiller - August 12, 2026, 01:34:04 PMThe days of the year are the same. They are both May 1969 castings. My advice, accept that both are original. The preponderance of the evidence suggests both are original to the engine. No need to prove otherwise. These are SAND castings, so they aren't always perfect.
Test castings would have M dates.
"There is one exception to the normal casting date convention. When the foundry was evaluating a casting process change, the foundries used special codes to indentify the test parts. Evaluation castings made at Flint received an M month code and evaluation castings at Tonawanda would typically have an X cast on the part. After evaluating the parts, the heads would either be destroyed or released into production. There is no way to determine the date an "M"-coded part was poured."
Test castings would have M dates.
"There is one exception to the normal casting date convention. When the foundry was evaluating a casting process change, the foundries used special codes to indentify the test parts. Evaluation castings made at Flint received an M month code and evaluation castings at Tonawanda would typically have an X cast on the part. After evaluating the parts, the heads would either be destroyed or released into production. There is no way to determine the date an "M"-coded part was poured."
#82
Originality / Re: Early Casting Date on the ...
Last post by COPOZ/28 - August 12, 2026, 11:50:15 AMEncouraging info -- thanks to all who responded. A friend took my question to a Corvette forum and received very similar responses to those here.
What about the possibility of the new-for-1969 head casting p/n 3927186 being introduced early, as a running change during the last 3-4 months of the '68 model year? If introduced early, and if Flint didn't spend tooling $'s for drilling/tapping the alternator mounting holes, were these new head castings ever used on later '68 engines with their left side alternator mounting provision remaining in place until the actual 1969 start of production, when the change over to the right side alternator location took place?
If that is unlikely (or never documented by anyone in CRG as having taken place on an engine), I would have to agree it is most likely explained by a digit that got "buggered up" a bit during the mold making/casting process.
What about the possibility of the new-for-1969 head casting p/n 3927186 being introduced early, as a running change during the last 3-4 months of the '68 model year? If introduced early, and if Flint didn't spend tooling $'s for drilling/tapping the alternator mounting holes, were these new head castings ever used on later '68 engines with their left side alternator mounting provision remaining in place until the actual 1969 start of production, when the change over to the right side alternator location took place?
If that is unlikely (or never documented by anyone in CRG as having taken place on an engine), I would have to agree it is most likely explained by a digit that got "buggered up" a bit during the mold making/casting process.
#83
Originality / Re: Early Casting Date on the ...
Last post by bcmiller - August 12, 2026, 08:07:37 AM8s and 9s often look alike with castings. Yours are 9s. I don't think they were being cast in May 1968.
We did this report on cylinder heads a while back.
https://www.camaros.org/cylinderheads.shtml
We did this report on cylinder heads a while back.
https://www.camaros.org/cylinderheads.shtml
#84
Originality / Re: Early Casting Date on the ...
Last post by KevinW - August 12, 2026, 07:30:48 AMI vote 9 on both heads too
#85
Originality / Re: Early Casting Date on the ...
Last post by buenymayor - August 12, 2026, 01:23:27 AMIt does look like an 8 for the year, but I'd say it is actually a 9 vs an 8. The odds of getting a head exactly one year off the other is pretty slim, and I don't think the 186 casting came out until '69, anyhow. I could be wrong on that, thoguh.
#86
Originality / Early Casting Date on the '69 ...
Last post by COPOZ/28 - August 11, 2026, 08:06:18 PMMy 05E Norwood '69 Z28 has a pair of the 3927186 cylinder heads on its engine and both heads have the bosses and 3 drilled/tapped holes for a right side alternator mounting location that was adopted for the start of the '69 model year. Right side head has a casting date code of E79 (May 7, '69). Left side head date code looks much more like E78 (May 7, '68) than it does E79 -- see photos. The engine build date per my P-O-P is 0513 (May 13th).
Has anyone observed a 3927186 head with a casting date as early as May 7 of 1968?
Has anyone observed a 3927186 head with a casting date as early as May 7 of 1968?
#87
1969 - Orphans / Re: V0425DZ 639617 ? On Faceb...
Last post by rocco376 - August 11, 2026, 06:31:59 PMSorry-thanks
#88
General Discussion / Re: Heater core rebuild
Last post by red69 - August 11, 2026, 09:57:03 AMThanks, I'll check them out
#89
1969 - Orphans / V0425DZ 639617 ? On Facebook
Last post by rocco376 - August 11, 2026, 06:09:58 AM1969 DZ Block on Facebook. New Jersey
https://www.facebook.com/marketplace/item/2079300809290886/?ref=browse_tab&referral_code=marketplace_general&referral_story_type=general_listing
https://www.facebook.com/marketplace/item/2079300809290886/?ref=browse_tab&referral_code=marketplace_general&referral_story_type=general_listing
#90
General Discussion / Re: "Boomer": My '67 Royal Plu...
Last post by David K - August 10, 2026, 09:27:21 PMFacebook marketplace and ebay are your best bets for NOS. Eventually you should make a connection but it all depends what you need. Since your goal is the Nationals, stick with the original parts on the car wheneverand wherever possible. NOS does not always replicate assembly line parts 100%. There might be a stamp missing, crimp not on a part, updated design, etc. Before you buy a single part, you need to contact Steve Shauger at "Vintage Certification" and have your car inspected. His team can determine what is original and not original parts to your car. Original parts properly redone always score higher.
https://www.vintagecertification.com/
https://www.vintagecertification.com/