So I just ran across a 2nd engine stamp in as many weeks that had the same issue: based on all other info on the car, the month of the build date of the Tonawanda block would most likely have been October (in both of these cases, 1969). So, on the engine code ID, I'd expect to see the digits "10" after the "T". However, I see an "I0". That doesnt make sense to me. Am I missing something? That 2nd character after the letter "T" should be the number "1", not the letter "I", right?

Incidentally, I think both may be restamps, but if that's the case, it's hard for me to believe that the restamper was so careless as to switch the "1" to an "I" and totally give it away that it's a restamp.

 

Yes, it is supposed to be a 1 (one) but nobody really cared much at the plant in 69 and all kinds of mistakes were made. My 69 is stamped T1020LM195733479 but it isn't like they tried to do a good job of it....

 

Alpha capitol Is were often used in place of numeric ones at Tonawanda. It is also common to see them together (i.e. T0I21xxx). The presence of either or both together does not necessarily mean a restamp.

 

Very interesting. I just learned something today. Not that I need another variable to account for in the already complicated world of engine stamping. But I cant imagine that these sorts of mistakes at Tonawanda don't lead to a ton of questions from astute buyers.

 

The use of Is and 1s was not a mistake at Tonawanda. It was common practice. You will also see variances with alpha Os and numeric zeroes.

Just a heads up on future Tonawanda stamps you might run across.

 

Yup, thx. Many lessons to be learned every day. Here's a pic of one of those stamps I mentioned in the original post and, no, I'm still not engine stamp smart enough to say whether this is original or not (aside from the alpha I to numeric 1 thing).

 

Most BB were stamped with I not 1. I always look close at stamps that have a 1 & not a I

 

lots of times your local restamper does not have multiple '1's or '0's in his kit, so he uses the I and O letters instead when there is a need for multiple ones or zeros.

 

So it doesnt sound like we have a consensus on this point. I guess like all things, we need to go back to the stamp itself. How does above pic look to you? I think I see the vertical and relatively evenly spaced broach marks, but then maybe again, I just want to see them. Impressions look about the same depth, and spacing looks relatively uniform. Edges don't seem too clean. Etc...

 

I believe it would pass NCRS judging.

 

The use of the letter 'I' in place of / in addition to the digit '1' is well documented for both small block and big block engines.

The 'I' and the '1' were used interchangeably by both Flint and Tonawanda engine plants.

I have seen many known original stamps that contain multiple 'I' characters, and no '1' characters. Something like FIII0xx (where xx is a valid engine code). I have also seen them mixed, as in the example above.

No real conclusion can be reached about the correctness of an engine stamp based on the use of the 'I' in place of / in addition to the '1' character.

This is one area where Al Grennings pad library really comes in handy. Since we know that the gang holders were set up at the beginning of each day with the date for that day, we would expect that all of the engines of a particular suffix code would have the same 'I' vs. '1' usage.

Note that each engine suffix had it's own gang stamp. So, as an example, for 1968 the Tonawanda plant would have had a separate gang stamp for each of the available engine types (suffix codes IL, IM, IO, IQ, IR, IT, IU) a total of 7 gang stamps for each day of production.

It is very likely that these various stamps sets used different 'I' vs. '1' configurations. So, take October 15th as an example. The gang stamps for that day COULD have looked something like:

T1015IL - two '1', zero 'I'
T10I5IM - one '1', one 'I'
T1015IO - two '1', zero 'I'
TI0I5IQ - zero '1', two 'I'
TI0I5IR - zero '1', two 'I'
TI015IT - one '1', one 'I'
TI015IU - one '1', one 'I'

So a total of 7 '1' characters and 7 'I' characters.

This is just a possible example, and not a representation of what actually happened on that date.

 

Thanks ..

I never knew that. Hum......interesting.

 

I did not know that, but it makes perfect sense.