Fake or real DZ stamp and partial Vin ?

[69 Zee]

Looking for opinions and help.  I'm seeking a real 69 Z either restored or in need of restoration.  I've inquired out an X77 and was given these pics of the engine DZ stamp and the VIN stamp near the Oil filter.  I'm waiting on a better pic of the TT.  It's an 05A build and so far the numbers align within.  Does the DZ stamp look to crisp and straight along the blocks edge or can that be the norm ?  Also am I seeing some other numbers below the VIN stamp on the oil filter location..looks like I'm seeing part of a 3 or 5 or maybe I'm seeing things.

Thanks

[KurtS]

Restamp

[6667ss138]

Yep, I was about to post before Kurt did that I would bet the experts won't like the stamps.

[1968RSZ28]

Restamp

Concur. 

Real deal attached...



Paul

[BULLITT65]

69 ZEE, your doing t the right way, keep posting pictures Kurt and the gang here will steer you in the right direction. KEEP SEARCHING BRO!

[69 Zee]

Thanks guys.. I was hoping for some fast feed.  I thought it looked to good and crisp and I'm just learning..lol  But most definitely will post. I'm no rush to get burnt.  Great site and I'm taking it all in.

Thanks gang ! 

[BillOhio]

I am curious, in real stamp pic,  aren't broach marks going wrong direction? Someone did do a nice job making the restamp block have nice machine marks. Are there shops using surfacing machines that leave this pattern or was it done by hand?

[bertfam]

I am curious, in real stamp pic,  aren't broach marks going wrong direction?

Those are machine marks made by a rotary machine when that block was decked. Luckily it wasn't decked enough to remove the suffix code!

Ed

[ko-lek-tor]

Are there shops using surfacing machines that leave this pattern or was it done by hand?

A friend of mine who does the swap meet thing weekly has many contacts and introduced a few to me while at a swap last year. In our conversation, restamping came up. These guys were telling me they can get anything done for a Camaro. They told me of a place in Ky. that will stamp block and has the exact broaching machine to resurface block. While I was surprised to learn this, at the same time, I was not surprised. I guess I have heard it all. Although I have no interest in this type service, I am aware now, that even the broaching can be replicated.

[69Z28-RS]

I think those machines aren't *real* broaching machines, but instead they have a mean to *simulate* the broach marks; how well that is done... is open to question... and there's the *age* issue; as a 40-50 yr old block shows other marks, crud, age, etc..  that they cannot replicate exactly (and even the accuracy of the broach marks they make is open to question).   When I see a 40-50 yr old engine that the deck surface is clean sharp and/or *painted*..   those are all clues to look a little further..

My understanding is that GM's broaching machines weigh many tons... I doubt these 'replicators' have that sort of machine available to them, and if they did.. my question would be..  how much material do they 'broach' off to remove all traces of the original stamping, machining, etc..?   I suspect they might fool *some people* with their approach...  but not all..

[cook_dw]

Before this goes further lets make sure we are not giving the "fakers" clues as to how they can better their craft..

[69Z28-RS]

I edited my post, DW...

[cook_dw]

I wasnt directing it to anyone because I know we all enjoy talking about these things and I dont want to see these types having an edge. 

[z28z11]

My understanding is that GM's broaching machines weigh many tons... I doubt these 'replicators' have that sort of machine available to them, and if they did.. my question would be..  how much material do they 'broach' off to remove all traces of the original stamping, machining, etc..?   I suspect they might fool *some people* with their approach...  but not all..

Excello LaPointe rack broaches are huge - individual racks, made up of many broach segments, can weigh thousands of pounds and stand 10-12 feet in length (and more). Machine bases and hydraulics are enormous. You're right - most of these guys that do this mill the blocks, and then work the surface to approximate broach marks (which you can usually spot right off).

The "real deal" pic above does show the result of milling - the curved lines you see are the result of the feed rate of the milling machine, and the ridge left by the insert radius on each circular revolution of the cutter. Whoever milled this one knew what they were doing - the mill lifted when it got to the stamping, a very light cut just to square the surface and clean it up. I'd bet the owner was relieved to see that -

[firstgenaddict]

I have also heard that someone in OH has a REAL BROACH as big as a locomotive is how the guy I talked to put it.
He was asking me about having a block done, I told him there is no way they are going to be able to get the broach to make the same tooling marks as originals... machines scraping metal away wear and the wearing will happen consistently, the broach marks from one month to the next will progressively change, approximating the change will be NEAR impossible given the number of legitimate broach photos on file with people who check and certify high end cars.
Someday we are going to cut out all this nonsense... I read recently that the vette guys are at least 10 years ahead of any other marque on being able to identify fake tags and stampings.