Solving a 3904351 stamping question.

[Joe M.]

Solving a stamping 3904351 question.
The casting 3904351 is not raised but depressed into the block. Has anyone seen this in the past? The suffix letters are JC and the build date looks as if its November. Any help with this issue is appreciated.Joe

[Patrick B.]

Re: Solving a 3904351 stamping question.

I have seen an early 67 car (Vin less than 1000) with a block that looked just like yours. It was a 1966 3869942 block with that casting number ground off and the 67 block number 3904351 stamped in. I have also seen very early 391 heads that were stamped over ground off 1966 858 castings. Your block was assembled November 8 whereas the other block was assembled in September, but your Tonawanda stamping looks completely authentic. What is the casting date of the block? I'm guessing it will be May or early June 1966 (E or F with 6 as the last number). I think 351 cast blocks started around June of 1966.

[Wayne M.]

Re: Solving a 3904351 stamping question.

Another photo example is shown in Colvin's '65-69 Chev by-the-numbers; page 62. On VIN 7115073.

[Patrick B.]

Re: Solving a 3904351 stamping question.

Yes, and both Joe's block and Colvin's photo show the same distinctive 9 and 5 characters in the 3904351 stamping. Colvin's photo block is really a late VIN which is surprising. Joe--what is the casting date?

[Joe M.]

Re: Solving a 3904351 stamping question.

Pat, John thanks for the help, I appreciate it verymuch. I have to get the block out of thetrailer tomorrow and will post the date code once I have it pictured. I also have another block to process and getcracked checked in the next week.

[Cecil L.]

Re: Solving a 3904351 stamping question.

Mistakes happen. The guy setting up the casting number in the pattern screwed up and it wouldn't be caught until later. If it could be corrected with a single digit grind and stamp, fine, but there were also instances where the entire number was wrong so it was ground out and restamped as shown.
I have one of the earliest 61 409 blocks (November 15, 1960) that has the entire number ground out and hand stamped due to a mistake in the casting number. The engine in the 61 Dan Gurney Impala was cast one day after mine and had the same mistake/correction. Later in the early production, a single digit was ground out and restamped.
Here is an example of an NOS early 62 409 block which was supposed to have the casting number of 3788068 but was cast as 3755068. This was probably due to the 348 casting using the same pattern but was # 3755011. The guy making up the casting number changed the last two from 011 to 068 but forgot to change the 55 to 88. This one got out the door uncorrected but others were corrected by grind and stamp.








And just for grins, here's my 61 409 block.

[Richard M.]

Re: Solving a 3904351 stamping question.

At the 2011 Winter Regional in Kissimmee I was OJ'ing 1967 Big Blocks, and a white/red L71 with a ground out 942 stamped 351 was being judged. It was a very early car, #664. I took many photos of the car, and one of the grind out numbers. Unfortunately this is my only photo(blurry) of the numbers......

P1270053.jpg

But it looked much like yours as I recall. The engine assembly stamp is T0906JE. I don't know the cast date.

P1270065.jpg P1270077.jpg P1270050.jpg

The owner was a great guy(white shirt in above pic) as he and I spoke much about his car and the unusual documented engine part# "stamp". I was restoring a L71 at the time and he was a wealth of information. He even let me hold those elusive "FB" tripower air cleaner base attach bolts he had in his pocket!

Unfortunately, the Florida Chapter website has not added any past results/photos/names of their Winter Regionals since 2010, otherwise his name would be there. If you drop a note to one of the NCRSFL guys they may be able to get you in touch with him. I have a pic of his license plate and he is from PA. I'd bet he'd give you much info and get some better photos for you.

Rich