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I just purchased 1971 LT-1 with a Car build date 1/7/1971 with a matching number block casting date L280 engine stamp V1230CGZ . Unfortunately, the last owner installed aftermarket heads and intake, Im currently looking for the correct date code heads 3973487 and intake 3959594. My question is what date code should i be looking for on the heads, and should both heads have the same date codes? Im finding some sets of heads that have different dates. Also it seems the intake date code is under oil splash pan on the bottom of the intake that most don't want to remove for a sale, does the intake date matter? Appreciate any help you can provide as i want to make this car correct as possible.
NCRS allows up to 6-months before car assembly, but that's stretching the typical foundry and assembly time frames by a fair bit. Also keep in mind that during judging, things like the valve covers are not removed to view the casting dates.
I don't know about the LT-1 intake casting date location as my intakes have the casting date on the top surface as far as I recall.
The head dates do not need to be the same date; I'd say the same day up to a couple weeks apart would be pretty normal. Both of my cars have the original head pairs within a few days of each other and, for each engine, they predate the block casting dates by a few days to a week or two. No matter what, make sure anything you put on the block has a casting date at least a couple days prior to the 12/30/70 engine assembly date stamped on the pad!
Hmmmm…. Since I am resto modding mine (1971 LT1) I wonder what I could get for the heads and intake. If enough to buy performance upgrades I could be convinced to sell them together.
Last edited by litevette; Jan 24, 2025 at 07:01 AM.
Hmmmm…. Since I am resto modding mine (1971 LT1) I wonder what I could get for the heads and intake. If enough to buy performance upgrades I could be convinced to sell them together.
Those heads are too late. They were cast after the original posters engine was assembled.
I have the intake dated right before your engine was built. Send me a private message if you want to discuss it. 3959594 intake with November 18th, 1970 casting date under the oil shield. Fits well with Dec 30th 1970 engine assembly date.
your best dates would be early to mid December, less best would be november or october. going 3 or more months behind engine assembly dates might get you those bragging rights, but it lowers the faith that they are original.
of course you have to take inventory and strikes into consideration. you don't know how and when the factory drew down its inventory.
I have looked for years for the right parts, and when a good date comes up, there is usually another excuse that comes up... for example the part needs a repair or has a un-repairable crack or needs a couple helicoils.
years ago i was looking for a block.. found the perfect date code, but it was already punched out .060 and had cracks and helicoils... =junk
1971 cylinder head date codes
