1968 Z/28 Block - Trans - Rear Numbers... Original Stamps?

[dannystarr]

Here is a very nice 68' Z/28 that was inspected by Jerry M. in 06' as ALL numbers matching drive train. But I am wondering if the block and trans are STILL the same ones since 8 years has passed. This car must be in the DB. Do the pictures match from 8 years ago? I worked on the pictures for quite a while getting them nice and bright, clear, cropped and resized.... Danny

[Mike S]

 Where did you get these pictures? Just curious.

Mike

[z28z11]

I'd like to see the originals. The engine pad has the appearance of being decked left of the VIN (see the outline in green), but unlike our discussion previously about restamping vs. decking originals, the VIN stamped edges are clean and sharp, suggesting the decking (or sanding/grinding) was done after the stamping, or possibly (if it was decked), the shop stayed off of the stamped area. Build date stamp and suffix looks correct, trans looks good, as does the axle.

The entire area has been sanded on the block - cleaning ? Removing feed lines ? Difficult to tell without seeing the balance of the deck surface.

[69Z28-RS]

I agree with Steve.  The deck definitely shows some 'machine' or other-than-broach marks, but the stamps appear original, and I believe there are faint broach marks still visible as well.

[Mike S]

  Study closely and you will see this block has a lot of surface rust scars on the pad area. I suspect a mild pass under the decking stone to clean it up was done so likely the whole head area was exposed and rusting. My 396 conv was taken apart by the previous owner after a rod bearing locked the motor in the 70's. He had since passed away and the car and parts sat in his back yard exposed to the weather. I bought the car and had to have the block decked to clean the rust off the exposed head mating surfaces (including stampings) so most of the VIN and prefix left behind is very-very light but still readable and there are still rust scars. Back in the 80's preserving a number wasn't thought of, with me at least, so when I had seen these pictures, it sure reminds me of what I went through.
  I'm still curious where these photos came from.

Mike

[Steve Shauger]

Look genuine to me. The area that looks decked appears to have light reflecting on the pad possibly causing the circular marks . I still see remnants of broach marks, but the pad has been hand sanded/cleaned probably to remove rust.

[BillOhio]

I like the light reflection over decked. If it was decked, by the way it looks, they would have skipped the whole corner of the block.

[dannystarr]

These are the pictures unedited. Not much more help... BUT..Take a look at these... Danny

[dutch]

I was just comparing the appearance and angle of the broaching marks that I have on my 302 block in addition to pictures that I have kept of other known good stampings, and all I can say is they don't appear to be at the 90 degree angle to the end of the block stamp pad area as the one I am referencing..
Whether that apparent angle is because of the perspective the picture was taken at or actually they are not square to the centre line of the bores isn't clear - but my impression was the broaching was done and therefore the marks created were always in-line with the bore centreline.. these appear in the posted pictures not to be!

[z28z11]

I can't dispute the originality of the numbers, but the marking to the left of the VIN looks less like reflections, and more like feed lines from a deck milling pass. Most decking is done with a milling cutter, not a Blanchard grinder, so the carbide inserts or brazed cartridges leave a feed line (similar to the feed lines you see on distributors after they are turned). I get the suggestion that the decking continued over the numbers, but since it has been stoned or abraded the feed lines are either extremely light, or were worked off.

The VIN numbers are uneven, and cocked. I checked out one of my original blocks, never decked, and the VIN stamp on the pad is very even, and uniformly light end to end. It also nearly gets into the build stamp on the block. Mine are very light compared to the pics above, which doesn't really point to anything with the exception of hand stamping with a gang stamp, which is not always consistent person to person, or strike to strike. I'm pretty positive the build stamp on the pic is original - same font (the "6" in particular) as my known original.

Broach marks are end to end, as the block was stood up and broached parallel to the crank bore. Broaching usually leaves a light straight line, end to end on the deck, with no angular marks. Angles are generally the result of hand scraping or abrasives (sanding, wire brushing).  

Just my opinion -

Steve

[JKZ27]

Looks to me like the pad/deck has been cleaned with Scotch Brite and someone is holding a round flashlight of some sort to get better lighting for the picture.

[dannystarr]

I too am going to say that the other white type markings seem to NOT be light. And if it IS gang stamped, why are some of the numbers so darn deep and the others light. Maybe that day the gang holders were missing, so they set up a straight edge jig and did it by hand? How can one 6 be so deep and the other 6 RIGHT next to it be so light? Doesn't make sense. I hope William, Kurt and some others chime in with info and maybe pictures of Jerry's report in 06'. My friend is looking at this car and forwarded the info to me. Then I have been doing my own research... Danny

[1968 Z28]

Danny......here is my original that is nine days later than the one you are displaying.  And no my VIN is not one digit short....the last digit is very light....you can barley make it out.

     

[dannystarr]

Yes, who knows. I see that last digit is very light. Looks like a "9" ? How can you hit them all super deep and then have one that barely shows. What the hell!!     I need a few more entries here, and some more explaining before I tell my buddy weather or not to pull the trigger on this car... Danny

[JKZ27]

Danny, I'm not a stamping expert here but it sure looks like what ever was used to stamp the VIN on the block was also used to stamp the trans.
I'm also gonna guess that the difference in depth and alignment of the digits could be caused by worn individual stamps and gang holders. We may have to wait until after the holiday for the experts though.

Happy Easter by the way.

John