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Chassis number conundrum

Posted: Fri Jul 07, 2023 10:42 pm
by Bigfoot
Can someone please advise as to the difference between the chassis number stamped under the radio compared to behind fuel tank. I was led to believe I owned a 74 911S but number under radio is 1065627 and number behind fuel tank is 911 4 300633, finally paint stamp on near side is 106 (but can see the 6 beneath the number 4) which is a later colour (Talbet Yellow)
It’s left hand drive and from memory body was originally from America and/or Japan as a track car so possibilities are endless…… before I look at restoring the car it would be useful to check it’s not a number of different cars welded togetherImage



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Re: Chassis number conundrum

Posted: Fri Jul 07, 2023 11:18 pm
by hot66
Under the knee pad is usually the build number which is different to the chassis number …. Or this is the case for long hoods anyway

Re: Chassis number conundrum

Posted: Fri Jul 07, 2023 11:28 pm
by 210bhp
Hi Adam

The ‘chassis’ number 9114300633 looks genuine and it is different to the ‘production’ number under the radio and bears no relationship to the chassis number. Only in early swb cars are these numbers the same. The production number can only be verified as a match to your chassis/vin number by the factory and I believe that is virtually impossible now unless you ‘know’ someone. The production number is the sequential shell build and therefore does not indicate whether your shell will become an S or a normal when finished.

I believe that 1065627 deciphers as the 5627th 911 coupe shell built in 1976 but others may wish to correct me if I’m wrong.

Regards
Mike

Re: Chassis number conundrum

Posted: Fri Jul 07, 2023 11:37 pm
by Bigfoot
Many thanks Mike. So looks like a 74 front end on a 76 main body. Been used as a track car for years by the looks so anything possible…..?


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Re: Chassis number conundrum

Posted: Fri Jul 07, 2023 11:46 pm
by 210bhp
Could be Adam if I’m right although on a second look there does seem to be some oddity around the ‘4’ on the chassis number, ??
Restamped a little heavier and a number rubbed off below?

Regards
Mike

Re: Chassis number conundrum

Posted: Sun Jul 09, 2023 8:15 am
by 1969.Carrera
1- original chassis (not replacement/not part).

0- 911/912 coupé made in Porsche Stuttgart (No Reutter).

6-model year (1976).

5627- internal serial number.

The number 4 stamped on the VIN appears to have been "chopped" over a number 6.







Re: Chassis number conundrum

Posted: Sun Jul 09, 2023 9:25 am
by Sam
Are the two zeros in the vin stamp different sizes too? There are companies that will X-ray the panel if you want to be certain but it looks to have had some restamping.

Lots of race cars have had new shells over the years for obvious reasons, I wouldn’t worry too much if you’re just going to knock about and enjoy the car. But if you’re about to commence a high level resto to create a high value car it’ll be looked at more critically when you sell it and people will be more concerned over the identity.

Re: Chassis number conundrum

Posted: Sun Jul 09, 2023 9:45 am
by Bigfoot
Yeah just a track car, but was thinking of investing some more money tidying it up with a new paint job, having almost made it road legal and rebuilt the 2.7 motor and gearbox…..probably won’t bother now


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Re: Chassis number conundrum

Posted: Sun Jul 09, 2023 10:59 pm
by RobFrost
Looks like there's a 3 under the zero in the number below the radio. Do you also have a number on the tunnel next to the gear linkage bracket, if you remove the vented plate?

I don't think a few discrepancies in numbers is a major problem in a 74S. If it was a 73S then it would be a whole different ball game.

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Re: Chassis number conundrum

Posted: Mon Jul 10, 2023 8:33 am
by 1969.Carrera
RobFrost wrote:Looks like there's a 3 under the zero in the number below the radio. Do you also have a number on the tunnel next to the gear linkage bracket, if you remove the vented plate?

I don't think a few discrepancies in numbers is a major problem in a 74S. If it was a 73S then it would be a whole different ball game.

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A three in the second position of the old PTN production numbers for a 911 is not possible.

0- 911/912 coupé Stuttgart.
1- 911/912 targa Stuttgart.
2- 911/912 coupé Karmann.
3- 914-6 Karmann.

Etc.

Re: Chassis number conundrum

Posted: Mon Jul 10, 2023 10:17 am
by Bigfoot
1969.Carrera wrote: Sun Jul 09, 2023 8:15 am 1- original chassis (not replacement/not part).

0- 911/912 coupé made in Porsche Stuttgart (No Reutter, no Drauz, etc.).

6-model year (1976).

5627- internal serial number.

The number 4 stamped on the VIN appears to have been "chopped" over a number 6.
So if the dodgy stamped number ‘4’ was a ‘6’ then it could match the production number?

Re: Chassis number conundrum

Posted: Mon Jul 10, 2023 3:25 pm
by 1969.Carrera

Bigfoot wrote:
1969.Carrera wrote: Sun Jul 09, 2023 8:15 am 1- original chassis (not replacement/not part).

0- 911/912 coupé made in Porsche Stuttgart (No Reutter, no Drauz, etc.).

6-model year (1976).

5627- internal serial number.

The number 4 stamped on the VIN appears to have been "chopped" over a number 6.
So if the dodgy stamped number ‘4’ was a ‘6’ then it could match the production number?
No, it cannot coincide because it fails in an important one, the year, they are different years/different PTN.

The PTN number indicates the model of chassis (911/912/914-coupe/targa) and manufacturer.

Also if it is the original chassis (1-) or a replacement chassis: 0- (with the VIN number without stamping).

It also indicates the year of manufacture of the chassis.

But for example it does not indicate if it is a chassis for an S or Carrera model, etc., in the last four digits (5627) there is the rest of the internal information about the chassis unit, you have to consult the Porsche factory about it.

Re: Chassis number conundrum

Posted: Tue Jul 18, 2023 10:13 pm
by Strictly
I think you already have your answers, but I can share a couple more things. The production number will also be on your doors in pencil under the window so take your door cards off and have a look, it may be difficult to see, but it should be there....if the doors are original of course or if they were swapped over. I have heard that the production number is also often written on the dash pad under the dashboard, but actually on my 79 it wasent there or anywhere else (only on two front doors, and on the dashboard knee area by ashtray.

For refernce my 79 911SC has production number 109XXXX and Chassis number 911930XXXX. I have looked at loads of 911's over the years with and without chassis numbers. In fact i recently looked at a 911 with a fake chassis number, which the owner had no idea about, until I showed him.

In your case your chassis number looks good, you can always look underneath and see if there is any evidence of the section having been welded in, its normally preety obvious. Generally LHD to RHD conversions lose chassis numbers when the bulkhead gets replaced, but not always I have seen conversions where the chassis number of the RHD car gets used in place of the original LHD body.

It should also be preety obvious if you have had a different dash fitted, just look for welding, and other clues. Im a bit rusty, but i think a 76 had twin vents in the centre, but im thinking that a 74 did not. Im not so sure, but there will be other clues.

I once passed on a 1968S with a 74 engine, and no stamped chassis number for £5k. It had been converted from LHD to RHD and the chassis number was ground off. The 68 VIN tag was all that remained. It even had a 6 digit number plate, valued at £8k at the time!. Lol, well i still stick to that decision - I like my cars to have true provenance.