Frame Stencil Date Code for 78 4-Speed
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Le Mans Master
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From: Myrtle Beach SC
Frame Stencil Date Code for 78 4-Speed
I have lots of information on M38 frame stencil date codes for 1978 Vettes but not much for four-speed frame stencil date codes. I'm looking for the suffix code painted onto the frame that follows the frame part number for 1978 Vettes with build dates after January 1, 1978. So here are the particulars for those that may have access to their vettes:
Location on frame: Passenger side front wheel well
Date code format = 1.18.78
Part Number format = 457981-204 or 207
Paint color = yellow
I suspect that due to the low number of four-speed installations, the lot number, or suffix was run from probably January into April. They would have had the same part date code (1.18.78) regardless of trim tag date code. In contrast, M38s had several different lot numbers during the same period and each of these would have had a different frame date code.
If you have something...let's hear about it.
Location on frame: Passenger side front wheel well
Date code format = 1.18.78
Part Number format = 457981-204 or 207
Paint color = yellow
I suspect that due to the low number of four-speed installations, the lot number, or suffix was run from probably January into April. They would have had the same part date code (1.18.78) regardless of trim tag date code. In contrast, M38s had several different lot numbers during the same period and each of these would have had a different frame date code.
If you have something...let's hear about it.
Drifting
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From: Kissimmee fl
Finalist 2021 C3 of the Year - Modified
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I don't know much about the codes, but I do have a 1" stencil making machine like the ones used by GM to make the stencils for the early C-3. Not sure how long they used the 1" tall letters and numbers, but I can make up any stencils that require that size.
Thread Starter
Le Mans Master
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From: Myrtle Beach SC
Thanks 69 but I've concluded the 78's were a 3/4" stencil. It seems the size varied all over the place throughout the 70's.
Thread Starter
Le Mans Master
Joined: Sep 2002
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From: Myrtle Beach SC
Update...on 1978 4-speed frame stencil
Update on the few I heard from in regards to frame stencils for 1978s. Here area a few highlights:
Now that the weather has broken across most of the country, if you're breakin out that 78 with a four-speed, check your frame stencil. Would like to hear from you.
Now that the weather has broken across most of the country, if you're breakin out that 78 with a four-speed, check your frame stencil. Would like to hear from you.
Team Owner
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From: Southbound
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I've read that the number following the GM part number for the frame is the A. O. Smith lot number. What I have not (yet) found is how A. O. Smith determined their lots. My hunch is numerical from the beginning of their production year.
Thread Starter
Le Mans Master
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From: Myrtle Beach SC
And I'm finding that M38 frames, due probably to the greater number of M38s sold, that the lot numbers ran higher than those for four-speeds during the same time frame.
For example, 1978 four-speed Corvette (VIN 0003) with trim tag date code of 3.18.78 had a frame date of 1.18.78 with lot #207. In contrast, M38 with trim tag date of 3.03.78 had a frame date of 1.13.78 and a lot #271.
Or consider lot #272 was used on 78s with stencil date codes of 3.15, 3.29, 4.03 and 4.18. So they do not appear to have been tied to assembly dates.
Go figure!
For example, 1978 four-speed Corvette (VIN 0003) with trim tag date code of 3.18.78 had a frame date of 1.18.78 with lot #207. In contrast, M38 with trim tag date of 3.03.78 had a frame date of 1.13.78 and a lot #271.
Or consider lot #272 was used on 78s with stencil date codes of 3.15, 3.29, 4.03 and 4.18. So they do not appear to have been tied to assembly dates.
Go figure!
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Le Mans Master
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From: Indiana
And I'm finding that M38 frames, due probably to the greater number of M38s sold, that the lot numbers ran higher than those for four-speeds during the same time frame.
For example, 1978 four-speed Corvette (VIN 0003) with trim tag date code of 3.18.78 had a frame date of 1.18.78 with lot #207. In contrast, M38 with trim tag date of 3.03.78 had a frame date of 1.13.78 and a lot #271.
Or consider lot #272 was used on 78s with stencil date codes of 3.15, 3.29, 4.03 and 4.18. So they do not appear to have been tied to assembly dates.
Go figure!
For example, 1978 four-speed Corvette (VIN 0003) with trim tag date code of 3.18.78 had a frame date of 1.18.78 with lot #207. In contrast, M38 with trim tag date of 3.03.78 had a frame date of 1.13.78 and a lot #271.
Or consider lot #272 was used on 78s with stencil date codes of 3.15, 3.29, 4.03 and 4.18. So they do not appear to have been tied to assembly dates.
Go figure!
Last edited by interpon; Aug 30, 2020 at 04:44 PM.
