How to tell GM fenders from aftermarket

[BULLITT65]

wow someone really liked HO enough to paint the firewall, heater box, booster, and brake lines. Thats dedication.
Have you located a DZ block?

[Emo1956]

LOL you notice that ha ! What a hack job. I took half the car apart  by just my hand so far. It took me about 5 months but I was lucky enough to have found the original block. The owner wants everything new in this car so I have been collecting parts for about 6 months. I am going to get rid of all the parts from this car for him so he can recoup some money.Look at the shim they used under the fender lol. This is the new dash I am building for the car.

[ZLP955]

Personally I would just hunt around for nice used GM fenders, they will be a fraction of the cost of NOS and you don't have to consider the fit and finish variances between early and late NOS stampings.

[Mike S]

Tim,

  How late were the NOS available from GM? I'm curious what the time frame distinction was between early and late. I heard the later NOS parts used a bar-code instead of a printed tag like the one I posted.

Mike

[69Z28-RS]

I'm with Tim on suggesting good southern/weatern ORIGINAL fenders/parts rather than NOS.   I suspect you'll have far less problems fitting them...

PS. for Bullitt...   EVERYONE loves the high output Hugger Orange Z's...     That's a HO HO for you Austin! 

[BULLITT65]

 
Well I am ok with Orange. But when it comes to painting the firewall, & heater box, I could deal with that on some rest mod I guess. The booster and brake lines though, come on...

I would rather see them in some aerosol overhaul fogged in black than the time it took them to do that.

Speaking of fenders though. I have two different markings on my white 69 fenders. Driver side has a half circle stamped out, just above where it bolts on the radiator support, but the passenger side fender does not have it. I am guessing one fender is reproduction?

[Emo1956]

OK here is what these fenders look like. They have the square nuts welded on. 1 inner panel says Twain and the other inner is a lot heavier.

[Emo1956]

More pics. The parts seem pretty heavy to me. Retros are liter and seem to bend easier.

[Emo1956]

Are these original ?

[69Z28-RS]

they appear to me to be GM parts (except for the TAiwain part).  Look on the flange as previously discussed to see if there's a 'week no' which indicates production line part; other wise probably an OTC part.  The black primered flanged makes me think that fender(s) were OTC parts.

[z28z11]

I've got a couple of '69 NOS fenders (R&L) if you need any particular views. I bought them in the mid 1980's from my local Chevy dealer, late '70's/early 80's vintage, long before they got discontinued. Extensions, too (were included with the fenders at that time). I can vouch for their age -

Regards,
Steve

[Emo1956]

Well I yanked the heads to find to my surprise 1 piston beat to hell lol. It looks like either someone dropped something down the carb or a plug broke off but that is a lot of damage for just a plug. I now think the engine is a 427 like the guy said when he bought the car. There is no counterweight on the balancer and it is a 4 bolt main engine. So maybe he got lucky and can recoup some money. I will know more when I pull the engine. Thanks to everyone for all the infor. You guys are the best. I hope the fenders are GM. Thanks Emo

[ZLP955]

Tim,
How late were the NOS available from GM? I'm curious what the time frame distinction was between early and late. I heard the later NOS parts used a bar-code instead of a printed tag like the one I posted.
Mike

Mike, can't answer that early/late timeframe with any authority, but as far as I'm aware, NOS fenders were available into the 90's but by that stage the tooling was worn, tolerances increased and panel stamping crispness and fitment reduced.
Most who have used NOS parts seem to recommend those with non-bar code part number labels as being better stampings than those with bar codes, or with 8-digit part numbers; but I'm not aware of when that transition happened.

[ssl78]

454 and 427 blocks are the same. If its a 427 it will have either a 7115 crank or a 6223 crank. If its a 454 it will have a 7416 crank.

[Sauron327]

   I have two pair of 69 fenders; one repro and one NOS. Both have square nuts as observed from the engine bay side. You cannot rely on the engine bay side view of square nuts in the photos posted. Look at the inside of the fenders. Repros may have conical and rounded tops on the backsides of the nuts, GM will not. There are no date stamps(run numbers) on the NOS fenders I have; however they are on assembly line take-offs. There are also no locator holes on the repro fender inner braces as on GM fenders.
    GM hood back sides are notched as in the photo B.A. provided but I've duplicated them with mild reworking. The front of a GM hood structure hem is well defined, not so in any repo hood. The spotwelds on the hood bumper contact discs are also different.

  Early stamping decals look like Mike's post, mid look like Bad Ass's for lack of a name, late had a bar code if at all. GM did not stamp these parts in the 90's. They were simply available at the dealerships as overstock. No factory stamps parts 20 years after production. They simply ended  up in warehouses as NOS.

 Made in Taiwan is self-explanatory.

  I like to use assembly line take offs even if they need work. I've had to throw a day of labor at some NOS bar coded '67 fenders to make them meet and exceed factory standards. Just installed a later 69 NOS doorskin that was double stamped at the bottom hem. Fixed it with a little extra H&D work but it proves that NOS panels are no guarantee. Common knowledge in the industry.

  All of this depends on the owner's goal and desires.