A Riviera scratchbuilt GT40

Hello members ,

The time is now arrived for me to post my first thread after several months of "guest" position on this forum ..

It has been such a major source of informations for my project that I feel now to have to "cross the border" and share my new experience on a GT40 MK1 scratchbuilt project.

I started 2 years ago from a "white paper", and despite not yet finished..., it comes now in the situation where I feel more confident and ready to exchange about it on the forum.

My first action was to spend some "Brainstorming " time in order to define the main objctives :

*"Sell" the project to my family ! No problem for this step and it is amazing to see how the GT40 image in evocating in France .

*Choose the "Scratchbuilt" route , body excepted : Cheaper ( may be...) longer of course, but so rewarding when it comes to be reality ...

*Decide for a track capability , but no racing : French autorithies are so unfriendly with kit-car builders that I immediatly decided to skip the road homlogation setp and to focus a track compatible design.

I may come back later on this issue ( SVA UK solution ?) Any advice on the subject is wellcome !

*Decide for my own design , with a friend of mine who is CAD "Solid Works" expert .
For this step, the main information source came from this forum and others : Cobra, Lambolounge, kits suppliers etc ..

As I got contact with Chris Melia, he sent me the interesting drawing package , Webguy.ca, which was a good asset for the design start up.

In addition, thanks to Chris, he gave me the opportunity to meet a former GT40 racing driver who owns an original full aluminum MK1, neaby my location on the French Riviera, close to Monaco .

Despite is car is not presently in road conditions, we had the opportunity to check all the chassis dimensions and we got wery productive informations that way .

I thinck to share the drawings on this forum if somebody is interested , after moderators acceptance, and after some basic validations :
body fitting, suspensions and uprights behavior, final torsionnal stiffness etc ..

As first overview, you can see attached the general chassis view ( Sorry, you may have to turn on the right orientation ..)

I will post soon on the detailled subjects : Chassis, suspensions, body, gear box etc , with some pictures .


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Randy V

Staff member
Lifetime Supporter
Welcome to GT40s.com Rene' .....

Nice drawings! I'm certain that there are a number of members here that will assist in the validation of your plans..

Please feel free to start your own Build Log in the Build Logs forum;
GT40 Build Logs - GT40s.com

We'd love to follow along, learn and even offer assistance if needed..
Thank you Randy for your welcome on the forum ..

I plan to continue hereafter the project description with more detailled data on the design features and the build up initial steps ...

As it is my first car build, I decided to stay on a "reasonable package" and it is obvious that the final result will not be an "historic" GT 40 replica ;

My main objective being to have the car on the road in some future , with acceptable track behavior , and attractive GT 40 MK 1 appearance ....

Chassis main features :
Space frame , stainless steel ( 304 L) rails, square sections: 40mm, 2 mm wall and 25mm 1.5 mm wall;

TIG Argon welding - A new technique for me ! Maximum concentration is needed to get an acceptable result !

For panelling I decided to go with aluminum ( 6082, 5083, 2 mm thick) despite I take the risk to get some future galvanic effects ...

I minimized the risk with strong SIKA bond interposition and 4.8 mm structural rivets systematic use .

I addition, as track oriented , the car will spend more of the time in a warm dry garage ( South France ...) and will be fully cleaned and inspected before and after each track day .

Of course , this solution would not apply for a road , day car ...

Before any chassis work, I built a strong jig ( 100 x 100 , 4 mm wall, mild steel) , bolted to the garage floor .
One leg is ajustable in orded to get a perfect reference plan.

Pict 4 - JIG .jpg

Despite it cannot rotate, I am very satisfied of this solution, as I always have a strong reference plan for any operation : Welding , panelling ...

For the time being, I only had to turn up-down the chassis 2 times for welding access and only one more turn is now needed before finalization..

The chassis is presently under build up as shown on the pictures .

Pict 10 rear .jpgPict 18 front .jpgPict 10 rear .jpgPict 22 rear.jpg

Body set: I decided from the very beginning to purchase a body set , instead of doing myself , as I know how a huge project can become a GRP creation ...

I got good advices and a nice offer from Chris Melia, but due to unexpected budget reduction, I finally went to the "Lowcost" solution with
Dan Miles/Darren George/GTStuning in UK .

The main features are :MK1, normal flares, twin nostrils , LHD with my own dash board ( I do not like so much the original one ..)
The set also includes the windscreen and door latches ;

The kit is under finalization, and I will get it in UK as soon as finished .

The "price/performance " ratio of this solution should be attractive, and I will post of course on the fitting step and final result.

To be continued ...


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Jim, Darnel,

Thanks for your encouragements ;

It is always better to have encouragements at the starting point, despite the finish line is still far away !

I have to say that taking and managing pictures are not my preferred tasks ... , but it is obviously a very effective way to communicate on the forum.

So I will soon post other pictures on the chassis, and other visible parts ...


Rene, that's looks like a very, very strong chassis.....and a good strong deck upon which you're constructing it!

How is the TIG welding going? I'd like to do some TIG welding myself....as it is, I can do a nice job of mig welding down to quite thin walled stuff using a very good mig machine I have...which is very fast to weld but probably not as controllable as your TIG. Have you cut open some test welds to see how is the penetration?

As it is ss that you're welding, I assume you're back purging the tubes? 100% argon shielding gas?

Keep up the great work!
Thanks Eglitom and Cliff Beer for your interest in the project ;
I will not hesitate to ask for questions, mainly when I will start to focus on the engine solution , as I have no experience on V 8 engines ...

Cliff Beer , to answer to your comments :

*Chassis is very strong : You are right, I oversized a little bit the main rails, pannelling etc ...

That comes from the" beguinner scratchbuilder" fear to under-size the chassis....

On the other side, I will not have brake assistance, nor A/C, nor steering assistance ; fuel tanks will be small : 5 gallons each ; seats will be lightweight, based on plywood epoxy kevlar/carbon reinforced .

At this day , the tub weight is 130 kg ( 288lbs) , and I expect to finalize it at 180 kg ( 400 lbs) ; and I aim to 1000 kg for the completed car ...

Achievable or utopic ?

*TIG experience : TIG technique was new for me, and I do not have experience with MIG ! My comments are :

-If you are familiar with MIG , with a top machine, you will get easily in the TIG technique as you can control your own welding speed .....

-The tungsten electrode needs maximum attention :

Right diameter ( same as welded metal thickness; ie 2 mm) , no pollution, right end shape grinding, and "touch down" during welding not recommended at all !

-I use a middle level machine ( 167 HF from GYS - 160 Amp max) with HF firing - This point is mandatory for me .... Amp tune :68 Amp for 2 mm thickness

-Stainless steel welding appears fairly easy, with easy melting ; you will have of course to deal with the wharpage which is worse than mild steel ...( That's the main reason for the strong jig !)

-I made penetration tests before starting the effective assembly : no major problems with 1.5 mm to 2 mm metal thickness.

- Back purging : I use a derivation on the the low pressure of Arg feed , but I must admitt that I often under-fed the parts due to the tremendous pressure drop on the ARG bottle !
Nevertheless, the visual result ( when control possible ..) is fairly acceptable .

So, I hope you get now fully confident to try the TIG solution ; have a good work ....
Well done, Rene, wondering how your build was going. Especially interested in if you have got your body set from GTS Tuning yet and what you think to the product etc.?
I am currently rebuilding a damaged 40 and will eventually be needing a body set, but at present rate of progress it won't be anytime soon!! I am also in France and have the same reservations as you regarding ever getting it registered for the road.
Best of luck with the build
The last i heard from Rene was this email he sent shortly after the body arrived with him.


I confirm you the body crate delivery on Tuesday 24 th at my home site ( Some date shift due to vacations period …) .
All parts are OK, no damage during the transportation ; thanks for the crate made …

I made a first positioning on my chassis ; everything is OK and should fit with minor adjustments .

As evocated , I plan to post positively on the body subject on GT40s.com forum ( if you agree …) .

Best regards


I've been waiting and hoping to see the progress he has made on here, but, nothing lately :-(

Hello members

I have to admit that I very seriously shifted on my forecast to post soon from my last post...
Some small things,as profession and family, to manage in addition to the GT40 project !

Nevertheless,the things have progressed .....

I received the body which was ordered to GTSTUNING :MK1 shape, with windscreen, white color.

The build time took approx.4 months, with close mail contact kept all along the stratification.

The parts where delivered from UK to France ( Truck ) in a specific wooden crate ; no problem at the opening .

The global feeling quality is good : Thick gelcoat, correct GRP thickness, no impacting bubbles....

I made a very first fitting on the chassis on order to fix the dimensions of the "superstructures" ( everything above sills level) which I had kept not built until I receive the body .

This rought fitting is very acceptable and the only point where I will have to adjust is on the front side of the doors to the rear side of the front clip..

At this step of the buid, I am really satisfied of the performance/price ratio of this body solution and I can recommend it to builders who have a "low cost" objective and a basic GRP experience.

To be continued ....


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That loks pretty good to me. The amount of adjustment needed to the body is minimal by the look of it. All 40 shells need some work on them to get the perfect fit and anyone expecting to just plop the panels onto their chassis and get perfect shut lines, etc are in for a big shock. Possibly accounts for a percentage of the unfinished kits out there!
Look forward to future updates.
scdavis, I am glad to see your positive impression on these pictures ; as it is my first car build up, and body installation of course, I do not know yet where to set up the quality objectives in this area of the construction ...

As I understood you where in in France, I sent you a message in the objective to get in direct contact and exchange on the poor French GT40 lanscape!
I may missed the message procedure; so, feel free to contact me from your side if you want .
Out of the points which progressed on the build, is the GEAR BOX :

I had the opportunity to get a used Porsche G50.00 box,year 1988 in fair condition.
It is announced for 80.000 km , with no LSD ; I got it for 2250 € to a local 911 specialist .
It has not been revised but it has ben agreed with the vendor that he will train and help me for any future maintenance ...

The main modification which I made immediatly on the box ( Not yet cleaned !), was to install a cable shifting system.

The shifter is the TOYOTA COROLLA 89 (Or 87 ...) which has been described on the forum;cables are from MIDWEST CONTROL 1/4 " ; and I made the box movement system with 2017 alloy , also from a solution seen on the forum ...

It is fairly compact ( Ie the rotating braket wings are 60 mm each ) and works properly , with hopefully 5 forward speeds and one rear ....

I moved the shifter lenght from 140 mm to 210 ( 1:3 ratio) , which gives a firm , but acceptable shifting in static conditions ; for dynamic behaviour, we will see ( much) later ...

I will post pictures on a next post , due to a file access problem !
Here are the gear box and shifter pictures pictures :


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Thanck you Molleur for your encouragements ...

By the time I designed and installed the shifting system , I continued working on the panelling, mainly the floor pan :

It is made from 8082 alu sheet, 2 mm thick, riveted with 3/16" alu structural rivets.
At the end, rigidity is very acceptable and resistance should also be ; but I do not plan to test it ....

I worked on the chassis turned up to down , and I hope it is the last time I made this flip up-down operation as I made it 4 times since the build start up !
The main reason is that I work with a floor bolted jig....


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Thanck you Molleur for your encouragements ...

By the time I designed and installed the shifting system , I continued working on the panelling, mainly the floor pan :

It is made from 8082 alu sheet, 2 mm thick, riveted with 3/16" alu structural rivets.
At the end, rigidity is very acceptable and resistance should also be ; but I do not plan to test it ....

I worked on the chassis turned up to down , and I hope it is the last time I made this flip up-down operation as I made it 4 times since the build start up !
The main reason is that I work with a floor bolted jig....