VIN stampings on Engine block and trans - process and details

[Gatorslayer]

I know this has been covered in many threads but I can't find answers to some specific questions/concerns I have about 70's stampings.

PROCESS - The threads say that the stamping is done by the worker by placing the numbers/letters into a "holder" and then stamping, which would seem to imply all the characters are in a straight line. However, I have seen many stamps that have the letters haphardly stamped, as if done individually, including my own trans from 1971 Cuda conv (see attached).I have also seen them done very straight, like on a 1975 440 block I just pulled from a Power Wagon (see attached). Also, stamped character size appears smaller on later engines (mid to late 70's). Did size change over years or differ by factory? (Mine is Hamtrack)

CONSISTENCY/WHEN STAMPED - Also, threads say that engine and trans are stamped at same time once mated, which would imply they should look the same, but I have seen many where engine and trans have same number, but are differently aligned on engine and trans.

Could they actually stamped separately in some factories or on certain cars (e.g. if engine/trans had to be replaced before it left factory)?

Again, I have seen many "numbers matching" cars where stampings have correct numbers on engine and trans, but not aligned the same on both.

Look forward to input from the group. Thanks.

[cuda hunter]

Very curious with the same questions.    

[mtull]

I know this has been covered in many threads

I'm looking forward to some education on this topic as well. 
@Gatorslayer can you share the threads you are referring to please?

[Gatorslayer]

How do I share threads?

[cuda hunter]

at the top of your browser will be a box that has the web address that you are at, Highlight that with your mouse, then right click and copy the highlighted address. Then come here and right click mouse and hit paste. 

https://forum.e-bodies.org/index.php?action=post;topic=29923.0;last_msg=325074
That link is this page here. 

[Gatorslayer]

The main one ifound it on was forebodiesonly.com (see quote below and I'll attach a screenshot of post. I'll also try to share the link per the last post above

QUOTE BELOW

That serial number stamping looks good. They used a hand stamp with a holder that held all 8 of the charters so they stamped all 8 charters at once. Also the way I understand it is they stamped the transmission and engine one after the other, after the engine and transmission were mated together. So the serial number on the transmission and engine should be identical. The sixth character (I think it is a "1") should look the same on the trans. The locations of the trans serial numbers depends on the type of trans.

[Gatorslayer]

Link.to above about VIN stamping on forebodiesonly.com


https://www.forebodiesonly.com/forum/threads/engine-vin-stamp-question.20289/post-117066

[Gatorslayer]

This thread shows a pic of the actual holder (attached)

https://www.forebodiesonly.com/forum/threads/engine-vin-stamp-question.20289/post-117066

[Gatorslayer]

Based on these links and the pic of the holder I don't get why my trans stamp looks so funky. It looks like the first 2 #'s ("1B", which is date and factory code) looks like it was stamped at a completely different time than the 6 digit VIN (which I could understand as it seems reasonable that those first 2 #'s are stamped when the trans was built and the VIN stamp came later when it was actually desinated or put in a certain car).

However, I don't get how the VIN stamps on my trans are so haphazard. It actually looks like the 1st 3 digits of VIN could have been in a holder and last 3 stamped individually. I can think of some possible scenarios (e.g. line worker lost his holder or broke his holder and didn't want to tell anyone so did by hand, broke holder in 1/2 so it could only hold 3 characters, convertibles were done by certain workers and built on a certain line so done different, etc.

Hence, my curiosity and looking to the forum for any clarity, info or thoughts on this?

(FYI - I know my stamp is real. Car was put in a barn in 1980 and stayed there until I pulled it out in 2002. It was clear it hadn't been touched all that time as it was sunk in dirt up to the frame rails and covered in 20 years of dust/debris.

[Gatorslayer]

Looking at the "holder" it does look like it would be quite a pain to find all the characters, load into holder and put cotter pin in to hold them (then redo for each, though you would only have to change the last few  characters for most of the day.

So many theories and speculation, but so little clarity or confirmation.

Very curious to hear thoughts of other ebody folks. Thx

[RzeroB]

@Gatorslayer Hi. Welcome aboard! First, congrats on keeping your car all these years! Smart man. Second, great questions, ones that many have been trying to solve the riddle of for years, decades even. I suggest you look at MMC Detroit's website. Dave has studied hundreds, maybe even thousands of the various alpha-numeric stampings found on these cars and has some good information on them on his site.

Now for my own speculation on the deviations in the stampings. Like you said, I believe it can be attributed to the tool itself, and the person manipulating it.

First, it's a hand tool that has to be held with one hand while striking it with a hammer in the other. The only way to get a perfect stamp would be IF it was held at a perpendicular angle to the surface and struck with a perfectly square blow to the head. Any deviation to the above and a less than perfect stamp will result. Stamping doesn't require a highly skilled person to do it, even an entry-level person could have been assigned to it. Stamping a couple of hundred of these a day I'm sure that person wasn't too precise in how they placed the tool on the surface and struck it with a hammer. I don't think they really cared as long as the result was reasonably legible.

Second, the tool itself. Like any other tool that you would pound on with a hammer, it's subject to accelerated wear and occasional breakage. I'm sure the individual stamps were NOT a precision slip-fit into the tool. There had to be enough clearance to allow them to be changed easily and not get jammed inside of the tool. This clearance, or "slop", would allow them to "wiggle" a little bit within the holder which in turn could result in less than perfect alignment of the entire stamp string. The individual stamps did not wear evenly. The characters on the left to start the sequence were constant and would wear out the fastest. The numbers on the other end of the sequence wouldn't wear as fast as they were changed out more frequently with each succeeding VIN. This would result in deviations in the depth and "crispness" of each individual character as there could be a mix of worn and fresh stamps within the tool.

Both of these things result in the "normal" VIN stamps that we see where there are deviation in the depth and alignments of the character string. Some of the stamps are pretty darn good while others are barely legible. I've seen "double-stamps" where I assume the first one was barely legible and they tried to "improve" it by striking it again but they never seem able to get them exactly aligned with the first try. I've even seen one where one of the characters was upside down on both the engine and the trans!

Looking at your trans stamp I can postulate a theory. Allowing for aforementioned "slop" of the stamps within the tool, all of your characters except the "B" are pretty much aligned along the same axis. As for the "B" it looks like that one individual letter was "over-stamped" over the sequence. Behind it and slightly to the left, there almost looks like there might be partial "ghost image" of the verticle "|" part of the "B"? It's alignment and spacing seem to be along the same axis as the rest of the stamp. Maybe the stamp-face of the "B" in the tool finally broke while it was being used to apply the sequence to the trans and as a result the "B" had to be individually over-stamped to complete the sequence?? All speculation on my part and I'm sure that it is something that you have already considered.

Anyway, enjoyed your post on this subject as it's one of those enduring mysteries that we've all given some thought to at one point or another.

[Cuda Cody]

That stamp shown does not look like the one I thought they used for the VINs.  Maybe someone has a photo, but I thought it was a wheel that was quick and easy to spin to the next number?

[Cuda Cody]

I'm pretty sure it was Dave at MMC Detroit who had the photo of the wheeled vin stamp.  He has done an amazing job documenting and helping the hobby.  His books are well worth the money.

[Cuda Cody]

All most certain I recall it was pneumatic and a dial wheel for the VIN stamping.  At least the body number where for sure.  And I can not imagine it wouldn't have been pneumatic.  Here's some neat photos while I try to find the photo of the VIN stamp.

[Gatorslayer]

That stamp shown does not look like the one I thought they used for the VINs.  Maybe someone has a photo, but I thought it was a wheel that was quick and easy to spin to the next number?

I got that "holder" pic from the link in the post above it so it have no idea if its accurate. It was on www.forebodiesonly.com