Ultimate ST thread

[HughH]

Continued

12) 00955 M491 customer car. Color blutorange / Tangerine . Deliver new to Gelo Racing Team Used by Loos for the 1972 season : Monthléry 1000 km Monza 1000 km Spa 1000 km Nürburgring
24 heures du Mans. Its engine is now in 9112301195 so possibly no longer exists



13) 00983 probably a M491 customer car as well but I don’t have a record of it

14) 00987 a M491 2.5 customer car for Willi Bartels. Gulf Blue. Great history still in Belgium was for sale this year. Engine, 6622035 documented as 911/73 M491 in sales material BUT 1972 wagenpass and other documents show as 70.4 x86.7 2492 with 270 PS at 8000 suggesting 911/70



15) 01019 delivered to Sweden? Probably a M491 customer car as well but I don’t have a record of it

16) 01144 delivered to Sweden? maybe a M491 customer car as well but I don’t have a record of it

17) 01155 I believe a M491 customer car as well but I don’t have a record of it. I note one document says it was Feustel’s car in the 80’s so that would make it a definite M491 (but different to the yellow one he now has)

18) 01195 a M491 2.5 light Yellow customer car for Anton Fischhaber TOL Y 25 1000 km Nürburgring 1972, car n°57, result : 14^th. solid race history 1972 – 1974. Engine 6622039 only described as M491 but elsewhere called 911/70 2492. Engine 6622034 also a 911/70 replaced original one “in period”.



19) 01328 probably a M491 customer car as well but I don’t have a record of it. Engine from it was for sale some time ago so may no longer exist. That engine 6622037 is a 911/73

20) 01417 a M491 2.5 light yellow customer car for Swiss Mr. Heinz Grieder. Today owned by Raceline (Feustel,) Germany. Engine 911/70 2492



21) 01687 a M491 2.5 customer car for George Stone and Bruce Jennings. Light ivory?? car #77 Daytona 24hr 1973 Upgraded in RSR Race history in 1973 / 1974 Lime rock, Daytona, Road Atlanta, Indianapolis... sold in 1975 to Vasek Polak raced 1976/1977 1982 / 1986. was under restoration





The total of definite and probably M491 cars excluding the 3 werks cars, is 21. There are 16 definite ones and 5 probable ones I suspect the 21 figure quoted for M491 2.4S customer cars built at the factory is probably accurate. Other sources have stated 24 cars but this may include the 3 werks cars? The others on the list are shown below and one or more of these may be a M491 Customer car, replacing one I have shown above as probable, to keep the total to 21 which is the widely quoted number of customer turn-key factory built M491 cars supposedly made.
Another source says only 20 customer cars were made with 10 to Germany, 4 USA, 4 Switzerland, 1 Spain and one France. No record of any to Sweden as shown on the two lists above and it does not gel with some other details let alone these lists.

[Darren65]

Wow....this thread just stepped up a notch or 10!

Great to have all this information in one place, thanks for sharing Hugh

[tomlin]

Great work, Hugh. Would love to have an info site on dedicated 1965-1973 race cars from Porsche per the chassis number. Or would that be illegal? These days it is quite simple to set up a Wordpress page.

[HughH]

Continued.. Can anyone help with the missing information here?

Others from the list



00045 I have never been able to find anything about 00045 but it is on a number of lists so may be a werks ST /SR given it looks like it was delivered without engine like the other two. There is no obvious competition car to match it to though. Possibly a Versuch car or a Werks “training car” but almost certainly not the Monte Carlo training car for Waldegaard, S-AJ 5964,which appears to have been 9113200022, unless anyone knows something different.




00863 I don’t have a record of it. Interesting that it shows engine 6630022; the engine that ended up in RS0012 which is currently single plug. I wonder if it really became RS0012 as the document shows that that engine was in RS#12 at least when the paperwork was done and RS#12 was on a 72 shell. David Mohlman used to own it and may know. Interestingly it (RS 00012) had order code 911/544 ie 911S with Carrera engine and 5 speed so it may have originally been this car. However it does not show “scrapped’ like 0841 so either the list is inconsistent or it did not get turned into a RS prototype.



00897 I am not sure. I have a record, but no proof or number, that it had a street 2.4 in it. I notice it has no engine number on my list but the same number as 00908 on the list



01047 No idea: I don’t have any records of it. It may or may not be a M491 car. Could be Versuch or family car



9112301514 was a S2.7 for Michael Piech with a “RS spec” engine 6620011 so these lists can’t be a list of all “M491 ST’s” but is obviously a list of special 2.4S cars.



01632 possibly a M491 customer car but maybe a Versuch car. I don’t have a record of it. The fact that it is shown as having a 2.7 leads me to suspect it was either a Versuch car or a S2.7 and either sold to family or friends as that (like the Piech car) or converted into one of the early RS prototypes.


There were apparently 3 2.7S’s built
Definitely 9112301514 for Piech
Possibly 9112300863
And one other on this list?? Possibly 9112301632?


Other customer 2.5 S M491 cars


I think that the M491 customer cars may be able to be identified visually, at least when new, by the rectangular cutouts in the from spoiler as well as racing in GT type events in 1972 and obviously having the oil tank in the 1972 position. Furthermore cars like this with s reference to Porsche sponsorship probably strengthens the odds. The following are some photos of cars that fit this description but I cannot identify the VIN numbers for. One or more may also be cars already shown above such as the Vasel Polak one were there was use in Europe in 1972 but no contemporary photos

This looks like one car #10 Jean-Pierre Jabouille (F) European GT Championship Paris 16 April 72. Interestingly it was sponsored by Porsche and despite the drivers obvious talent as a F1 driver it is shown as "did not qualify" for this event.






Could this be 1144? or perhaps 1019? the two cars that are shown on both lists as for Sweden? The first photo is Zeltweg 1000 Kilometres 1972 Porsche 911 S no.32 25 June 72 Team Kuberol Racing Colours: red (+black/yellow) Driven by: Bengt Ekberg (S)Roland Larsson (S) listed, never drove: Kurt Simonsen (S) - Porsche F6 2492 cc N/A

and here it is at Nurburgring in colour


The last one I have at present is this one from the Norsering in August 1972 #4 for the Hulpert Racing team with Gunter Schulte as driver. There was at least one other customer M491 car at this event (0987 with Heinz-Jorgen Dahmen driving and entered under his own nme as well as another car entered for the Huplert racing team for Jurgen Krizkalla which was probably 00934.


this one may even be the yellow car 0495 that went later to Vasek Polak

Any leads on any of these cars or teams such as Hulpert or Kuberol that may lead to tieing cars to them would be helpful.

Finally I have started trying to reverse engineer this list by listing all of the engine numbers and putting cars against them. As mentioed earlier this was helped by details in the new RS book showing engines used in some of the 1973 RSR "R" cars. I dont know if all or any of the engines between 662 2009 and 662 2018 were made or not but the numbers up to 2010 seem to be werks cars and some at least, maybe most , were eventually 2.8 RSR spec in some form or another. the ones from 2021 to 2041 seem to be initially for the M491 customer cars. There is evidence elsewhere that the Stone car (1687) was definitely the last one built so this supports the view that there were likely 21 customer cars. the boxes filled in in green is where either I have seen primary source documents confirming the data or DrK has it in the RS book which again went from primary documents. There are still a lot of gaps though .

[928cs]

Impressive work. Thank you for sharing

[Jim Garfield]

Excellent work Hugh. Very interesting to see the history of these cars so thoroughly documented. Thanks!

[letsrollbabe]

Hugh,

You have done some great work here...thank you.

As we have discussed offline, the factory was developing a 2.7L engine for the 911S for 73, and so had the 90 mm Nikasil cylinders under development. The 2.8L engine configuration used the same spigot opening as the 2.7L (97 mm), which was slightly more than that used on the 2.5L 662xxxx engines (94 mm). I also think Mahle bored the 92 mm cylinders from the 90 mm versions, and produced a 92 mm set of 10.3 pistons to make 300+ hp. My guess is that those 2 twin plug 2.7L engines listed were most likely a development step in between the single plug 2.7L for the 73 911S/ RS, and the 2.8L race engine. The twin 2.7L would have only required a higher CR set of pistons and twin plug heads with no change in the combustion volume or valve sizes (but with opening the spigots from the 2.5L). The 2.8L heads had a larger combustion volume with larger valves, so more development work req'd. But the twin 2.7L probably produced something around 285-290 hp with the race cams, and not the 300+ thought to be needed to be competitive in 73. As you point out, these could have been built for a family member or special customer, but would have been tested on a dyno to determine the HP possibility for this displacement.

Another factor for these 662xxxx engines that has not been discussed is how they were rebuilt during a race season, potentially with new cases...and were these blank cases renumbered, and if so by who...the factory or customers? That could account for 662 engines becoming 2.8L later. Maybe not many required case replacement, but switching from 2.5L (911/73) versions to 2.8L (911/72) versions would have been an ideal time for a case change since it would have req'd the case halves to be parted to machine larger spigots.

[Chuck Miller]

WOW Hugh !!!!!!!!!!!

[wgm]

Excellent work, as always, Hugh, thank you very much for sharing your efforts!

Regarding to #1019
Armando's statement that this was delivered new to Spain, could be the right choice:
There are two pics, which show an apparently Rallye-optioned 2.4S or M491(?)
First one I had on file, tagged as factory tour'72, the other one Gargallo/ Ramon at the Rallye Bosch '72, still with German customs plates("Zollkennzeichen")




Regards
Wolf

[wgm]

As to the Team Kuberol Racing 911:

First, the rollbar strut is behind the driver, which was not the case with the 2.5/ M491 imho - see rearview pic(#0872)

I think, this one is one, which was developed by the Kuberol Racing Team from a standard 911S or T - see development stages, pics attached