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I would like to know if the factory ever double stamped pads when they didn't appear correct. If so can you guys post some pictures of them. Whether it be the Vin. or the Engine code. Thanks
I've seen it before; but this is unlike the thread awhile ago where only the two letter engine suffix was double stamped - that was clearly some chicanery going on and nearly impossible to do with a "gang" stamp....
I would like to know if the factory ever double stamped pads when they didn't appear correct.
To double stamp a pad when it didn't appear correct, would be highly unlikely. GM was not building show cars, and didn't worry about things like the appearance of something as minor as the stamping on the engine pad. Double stamps were usually the result of the person doing the stamping, accidentally doing a double tap, or something similar. Normally if the VIN or engine code were stamped wrong, they would grind off the bad stamping, and then restamp it, not just stamp the correct info over the bad.
I did some gang stamping in the 70s at the Naval Air Station. Pretty common to do a light "test" tap on the gang stamp to make sure its aligned and completely horizontal to the surface and to line up the hammer sweep and then do the "real" bang with the hammer...
If the stamp faces are new and sharp the "test" tap can lightly stamp the surface...no great mystery...
I used to own a 73 convertible that had the last digit of the VIN OVERSTAMPED on both the engine and transmission. The first stamp had the last digit as an '8', which was then overstamped with a '7'. '7' was the correct digit.
The car was a base motor automatic, and this was 1988, so I am confident that this was a factory "adjustment".
I've posted on this subject before but for those who may have missed it. When I worked at the Fremont Plant (‘65-'82) I saw a lot of poor quality VIN stamps go out the door – it just wasn't very important back then. If there was a "readable" stamp somewhere, it was OK. Who knew we'd be looking at engine pads under a microscope 50 years later?
Holding a gang stamp in one hand and striking it with a hammer is more of an art than you might think, especially with engines moving at a line speed of 45 units an hour (Fremont) and the operator having tasks in addition to stamping. There were light strikes, uneven strikes, and multiple strikes with the gang stamp; single character repair stamps, and even alternate location strikes on the side of the block (cast surface - allowed on A-Body Chevy blocks). Assembly plants were supposed to “X-out” bad stamps and stamp again but over-stamps were the norm. If inspection wrote up an illegible stamp, the repairman usually restamped the necessary characters with single stamps, not a gang stamp. When the regular operator was absent, a replacement (or two) would try to perform the stamping operation, having never done it before, at 45 jobs an hour, and it wasn’t pretty – oohh, the 60’s!
Now, others like JohnZ, have posted that VIN stamping was better controlled at St. Louis (much slower line speed) but I've seen some examples that were reminiscent of Fremont. The example below was posted by a '64 owner several years ago showing illegible over-stamps and a readable stamp in another location.
11-06-2019, 04:40 PM
Engine pad stamps
