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What's the opinion on this L-88 Stamp?

astrolake

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1968 L-88? red conv
I'm posting a photo of the engine stamp on a car that appears to be an L-88. I'm curious as to opinions about this stamp. I'll post photos of the car and the entire engine if I don't hit some limit on size. I'm told that fake stamps "look too perfect". It doesn't seem like a Swiss thing to restamp cars, but they are certainly master craftsfolk.

I found--and bought--this car in Switzerland. The Swiss love US big blocks (gas taxes have always been low by European standards). I will ultimately sell it in the US, but how to represent it is tricky given the large number of fakes. The numbers all match. It's in nice condition as the Swiss have rigorous inspections every 2 years. At one several years back, the previous owner was forced to change the gas tank as there was visible rust. He declared the sticker to be unreadable (I understand that there were sometimes build stickers stuffed elsewhere, but given that he found an unreablbe one, I suspect that means I'm out of luck if I try snooping around?). For what I paid, it would be good value as an L-88 clone, but so far, it looks to me like the real thing. It has been repainted, the original color was green. Damned shame that there isn't a master database like Ford's MARTI, alas.

Clearly, given the number of fakes, I need to find a good venue to sell it where someone can see just what it is (or perhaps isn't), probably an auction associated with a Corvette event, preferrably in Florida where my brother lives. Any ideas on that? The car is still her in Switzerland with me, I garage it across town and given the weather, it gets little use, given the great trains, my normal road car gets extremely little use.

The car runs on pump gas, which is much higher octane than US pump gas, but not 103. The vacuum advance is disconnected, but I fear that the engine may have been detuned in other ways to make it more of a street car.

Thanks for sharing your opinions here!
 
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1965 Coupe L76 / 1978 L82
I'm NO expert by any means but it looks like you have broach marks going in both directions on the stamp pad which would indicate the block was decked. Usually that removes all the numbers so that makes it a very good chance this is a messy restamp.

2nd, the car has ignition shielding on it....... L88's were automatically a radio delete car so they came without any ignition shielding.

Wrong air cleaner and valve covers......

is there a radio and heater in the car? That right there would give you your answer.
M22 trans?

sorry, not trying to critisize your car by any means, but pointing out the things that are incorrect for a L88 car.
 

astrolake

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Europe
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1968 L-88? red conv
Follow-up, keep the analysis coming!

I'm NO expert by any means but it looks like you have broach marks going in both directions on the stamp pad which would indicate the block was decked. Usually that removes all the numbers so that makes it a very good chance this is a messy restamp.

Thanks, I have googled but not found images of engine stamps. Generally there are the remarks that restamps look too good and the factory did a messy job... Does anyone know where there are some sample images of original stamps and restamps?

2nd, the car has ignition shielding on it....... L88's were automatically a radio delete car so they came without any ignition shielding.

Wrong air cleaner and valve covers......

is there a radio and heater in the car? That right there would give you your answer.
M22 trans?

sorry, not trying to critisize your car by any means, but pointing out the things that are incorrect for a L88 car.

yes, it has the M22 trans and its number also matches. Also, the brake booster and radiator are correct. There is an aftermarket radio and the ignition shielding was added for it. As I understand, radio and heater deletes were the norms, but some states/countries required heaters, so this isn't definite.
 
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astro, my main point on the stamppad was that the actual broach marks are just as important to look at as the stampings themselves.

BTW, do you have the casting numbers and date of the block and how does the block date compare to the build date of the car?

just be aware, as you probably are, that real L88's are very rare ( I believe in '68 there were only 80 of them) and are worth a LOT of money. Even if the stamp pad broach marks and stampings look good, and everything else checks out, without actual documention of the original tank sticker, and/or window sticker, and/or other documented proof there will always be doubt about the authenticity of the car. Too many of these cars have been conterfieted so people can try to get big bucks out of them.
The running joke regarding the '67 L88's for example is that out of the 20 L88's GM made that year, only 135 documented ones still exist! :lol:
 

Vettehead Mikey

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The car runs on pump gas, which is much higher octane than US pump gas, but not 103. The vacuum advance is disconnected, but I fear that the engine may have been detuned in other ways to make it more of a street car.

Thanks for sharing your opinions here!

I'd almost be willing to guarantee that this is not a factory stamp, there's no real similarities at all to a 'real one', especially the double strike on the first 'O' in the engine assembly date. Does the VIN derivative match up with the car it's installed in?

The fact that it runs OK on pump gas is another 'danger sign'. European gasoline is the same octane level as US gas, they just use a different rating system. European 98 is equivalent to US 92 more or less.
 

6880 Mike

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1968 convertible; 1980 L-82
It is my understanding the engine assembly state stamping should be in 3/16th" characters. Those pictured are much too large. The VIN derivative stamping appears to be the correct 1/8" characters. The engine assembly date is June 30 while the consecutive unit number in the VIN shows a '68 Corvette produced in November 1967. I would have to question why an L-88 assembled in June (67?) was installed in a car produced six months later, but stranger things have happened. The IL code also indicates aluminum heads.

At the least, the engine code is possibly a restamp, but that does not negate the possibility the block is original. Casting numbers from the block and heads might help unravel the mystery.
:)
 

astrolake

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1968 L-88? red conv
At the least, the engine code is possibly a restamp, but that does not negate the possibility the block is original. Casting numbers from the block and heads might help unravel the mystery.
:)

Fantastic, this sounds like a chance to verify or deny. Where are "casting numbers from the block and heads" found? How do I decode?
 

astrolake

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1968 L-88? red conv
astro, my main point on the stamppad was that the actual broach marks are just as important to look at as the stampings themselves.

BTW, do you have the casting numbers and date of the block and how does the block date compare to the build date of the car?

just be aware, as you probably are, that real L88's are very rare ( I believe in '68 there were only 80 of them) and are worth a LOT of money. Even if the stamp pad broach marks and stampings look good, and everything else checks out, without actual documention of the original tank sticker, and/or window sticker, and/or other documented proof there will always be doubt about the authenticity of the car. Too many of these cars have been conterfieted so people can try to get big bucks out of them.
The running joke regarding the '67 L88's for example is that out of the 20 L88's GM made that year, only 135 documented ones still exist! :lol:

Yes, I know that there are more fakes than the real thing and this has to be considered the default, but I've been told that the odds are much better for finding a real one here in Europe, esp. Switzerland. If it's a clone, I'm certainly willing to represent it as that and try to make it a more faithful one at the same time. But, of course, it's thrilling to find a real one and I'd like to do what I can before I accept the clone status.

Another poster mentioned "block and head casting numbers", what should I look for?

Also, am I wrong or is it the case that an L89 has aluminum heads and an iron block---and that every car but an L88 has an iron block whereas the L88 is aluminum. Is the aluminum so reinforced with alloy that a simple
magnet test is nonsense?

I do appreciate the remarks, all of which are sensibly skeptical. I don't want to do anything to misrepresent this car, but would love to know what it really is.

Thanks for the help!
 
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'67 Marina Blue Convertible
Clearly an (amateur) re-stamp, both the engine code and the VIN derivative, and no 1968 model year engines for cars assembled in November were built in June of 1967 (and '67 and '68 L-88 engines were different).

All 427's had iron blocks, and L-88 and L-89 cylinder heads were aluminum.

A November '67-built '68 L-88 would have a 3916321 block (casting number on rear flange on driver's side, behind the cylinder head, where the bellhousing bolts to the block), and the casting date code is down on the passenger side of the block, just forward of the starter, upside-down, near the freeze plug. Cylinder heads would be casting #3919842 (casting number and date visible after removing the valve cover), aluminum, and should have a large threaded plug in BOTH ends of the head. Post the casting numbers and dates for the block and heads and we can probably decipher what you have.

Heater delete (required on '67 L-88's) wasn't available after 1967, as federal regulations required a heater/defroster from '68 on.

:beer
 

rocket22

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mo
Didn't all 427's use the same block,I believe that 435 horse engines and l88's use the same block.So it could be a replacement motor or the original engine.
 

Evolution1980

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This is really trivial in the grand scheme of things, but that's also not an L88 hood, if I'm seeing the picture correctly. The L88 hood had 2 section rises (of sorts) to the cowl, not just a single rise.
 

redvett

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L-88's & ZL-1's didnt have a vaccum advance just an inoperable can with no hose fitting and a draft tube at the rear for crankcase vent & no PCV. Also they had an aluminum radiator with the S/B overflow tank.
 
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L-88's & ZL-1's didnt have a vaccum advance just an inoperable can with no hose fitting and a draft tube at the rear for crankcase vent & no PCV. Also they had an aluminum radiator with the S/B overflow tank.

That was only true in '67; in '68 and '69, L-88's had full emission systems (A.I.R.), and full PCV systems.
:beer
 

Evolution1980

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Also, that car looks like it's Mille Miglia Red w/ White top. There weren't any L88 verts that I'm aware of. That would seem to be the most obvious indication right there... :confused
 

Evolution1980

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Leave it the General to make a one-off. (Were there more???)
Interesting little note at the end of the article... There was a "Charger 500 Hemi" that did the quarter mile quicker???
The article stats show the 1/4 mi in 13.56s. Yet it's been stated that the L88 did them in 11-12s. I'm gonna have to research this Charger 500 Hemi. Sounds like a beast itself!
Did ya notice the mileage listed for the L88? :L ...and there was an "oil crisis" why??? :L
 
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At one several years back, the previous owner was forced to change the gas tank as there was visible rust. He declared the sticker to be unreadable (I understand that there were sometimes build stickers stuffed elsewhere, but given that he found an unreablbe one, I suspect that means I'm out of luck if I try snooping around?). For what I paid, it would be good value as an L-88 clone, but so far, it looks to me like the real thing. It has been repainted, the original color was green. Damned shame that there isn't a master database like Ford's MARTI, alas.

astrolake,

You can call the nice lady at GM. Give her your VIN number, and she will send you a build sheet with all the specs on the car as it left the factory, as well as the name and address of the dealer that it was shipped to. I don't have the number handy right now, but I'm sure someone here at CAC can post it, or search and find the old thread about it.

Semper Fidelis,
Culprit

PS - depending on the year of the Vette, they might not have the records going back that far. My Vette is a '78 and they had mine - that's all I can tell you. Someone else jump in here...
 
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Leave it the General to make a one-off. (Were there more???)

Yes, there were more. ;)

The article stats show the 1/4 mi in 13.56s.

Rear diff ratio -- 3.36:1 If you're going drag racing, you don't choose 3.36:1 gears. Did you notice the tires? Not even radials in those days. Throw a set of slicks and 4.56:1 gears at it and get back to me. ;)
 

Evolution1980

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Rear diff ratio -- 3.36:1 If you're going drag racing, you don't choose 3.36:1 gears. Did you notice the tires? Not even radials in those days. Throw a set of slicks and 4.56:1 gears at it and get back to me. ;)
I thought all the L88 came with the 4.56 gearing. 'Course, I thought there were no vert L88's either. :L
And yeah, I know the tires weren't slicks on showroom cars. When GM claimed their 11s quarter mile, was that on 7" slicks or something? ...(getting off topic here)...
 
W

WhiteKnight

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That article looks like a pretty rare L88 indeed (auto trans) which is why the ratio was limited to a 3:36. The pics in it should give Astrolake some ideas on what a correct car looks like, hood, engine etc.

The current record for a L88 running in F.A.S.T. is high 10's. That class is "Factory Appearance Stock Tire". So it was on bias ply tires, but not sure if todays compounds are "better" than what was available 35+ years ago.
 

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