Building a Gr4 replica

Fantastic job , A Gr4 (replica) is also on my wish list .

all the best into the New Year .

Simon

I can hear it now going up and down the parking ramps at the mall screaming at 9,500 rpm! I want to say, shift into second now!

OK, loooong time since some updates on this project.

After deciding to run the Gr4 car in the Danish Hillclimp series, and getting confirmation that it is in fact possible to classify the car in the Competition (B) Class for modified cars, I seem to have found some motivation to try and move the project along.

We did go through the engine - just to make sure everything is fine. So everything was inspected cleaned and found fine and put back together.

We replaced the main and rods bearings (some trick Elliot Coated parts from Yates), Cometic gaskets and vacuum seals and the crank was polished (just as a precaution). But everything were looking good.

Also had Scott at Eatmon Race Engines design a new cam for it, that moves the powerband somewhat down - i.e. with a max power around 8300 rpm but with a  stronger more usable midrange. Still a pretty aggressive cam with a duration of 266/270 at .050. Power is reduced to around 750 hp.

The RYRE D3 heads had the titanium valves replaced,  installed new PSI valve spings to match the cam and was vacuum tested.

Just need to degree the cam (the cam has 102/103 centerline) and the engine is all ready.

Maybe it's time for some updates on this wicked thing ....

I  notice you are using a timing belt ?

what brand ?

Simon

It looks great!

Looks fast!

Thanks for all the comments - to Simon, the belt drive on the engine is a Roush Yates.

Here's a little bit of an update on the project - it's been going a little slow but I did finish most of the modifications to the front-end of the car. Remember the car is being build to replicate the early gr4 Panteras (from pictures), as they looked when they first hit the track i the spring of 1972.

Here's the front - the huge oilcooler, brake ducts w/scoops cut into the front, modified grill (yes, I cut up a perfectly fine early chrome grill to copy the gr4 look - awesome !!!:-) ), aluminum headlight buckets incl manuel raising mechanism, aluminum hood and just finished copying the blade spoiler in aluminum (need paint).

Pretty time consuming work

Looks Fantastic, thanks for sharing .

How does works the manual rising mechanism ?

more pictures are welcome.

Simon

what rim size F+R and brand of tires are you planned to use ?

Simon

Fantastic work as always, many of the current crop of Group 4 race cars seem to have acquired the later GT5 style air dam. What brand tires do you have? I would be interested to see the headlight mechanism. Will you be  replicating the adjustable sway bars as well?

Yes, the Gt5 airdam is probably much more effective than the simple blade spoiler - but that's not the point in this build :-).

The wheels are the Marvic Gr4 magnesium reproductions , 10X15 front and 14X15 rear. The tires are Avon all weather historic race tires, 10.5/23.0-15 and 14.0/27.0-15, that was what I was recommended to use by Patrick Hals.

For the raising of the buckets, I keept the the original gear, and removed the motor and did some trimming of the brackets (had to because of the radiator). So I can raise the buckets manually with the emergency knop. The whole set-up is removable including the aluminum bar. I only have this older not so good picture - I have made some smaller trimming and changes to the set-up since then.

I intend to have the original adjustable Gr4 sway bars fabricated. I do have the drawings and measurements of them, including the modifications that were done to the a-arms and the chassis - the center mounts were moved outwards in the rear.

I would need to find a company that can build the sway bars though - any leads? Julian, if you are interested in a set for your car too, maybe we can figure something out.

Kristian

I don't know what kind of bars you will be using but this company built custom axles and custom hollow anti-sway-bars for my race cars many years ago. Great job and no failures.

https://swayaway.com/

@push1267 posted:

I would need to find a company that can build the sway bars though - any leads? Julian, if you are interested in a set for your car too, maybe we can figure something out.

Kristian

Maybe I am also interested into the sway bars ,

Simon

I was assuming I could just fabricate adjustable end links for my current sway bars, but certainly if the correct ones are available I would be interested in a set.

Here's the finished spoiler mounted - sorry for the bad picture quality. Pretty happy with the result. The front of the car sit 7-8 cm (3 inch) above the floor .

The factory car for comparison ...

good news to see that this beautiful replica is progressing well  !!!!!

It looks like an Italian movie star in a red dress. Very sexy, especially from the back. I'd definitely send over a drink.

Don't you need to run Webers like the factory cars did to qualify for vintage?

48 IDA Webers were homologated for the Gr-3 and Gr-4 but were options. The Holley #213 (list 4778) was the carb mostly used, I think. You do know there's a Swedish-run Registry for Gr-3 Panteras with a 14 page Supplemental Parts List that covers Gr- 3 and 4 parts. Browse to www.scuderiadetomaso.se, run by Anders Hellburg. He's still active- got an e-mail from him last week.

Hi Boss,

are you sure that it was a Holley 4778 that was specified in the supplementary parts list for GR3 and GR4? I think it only says List 213, which doesn't seem to correspond to anything, and everything I have seen posted seems to suggest great confusion about what the mysterious Holley 213 carb is. I speculate it is a date code and someone messed up when writing down the Holley model number and put the date code instead.

Cheers Tim

Kristian, great to see you working on the GR4 again - seems like the drive in the Grønne djævelskab did you some good :-)  There is a funny discussion about it on the FB page for Copenhagen Classic Car Group.

Cheers, Tim.

Yes, the green PB creates quite a stirr everywhere it turns up.

Regarding the carburators used, I do not know which one they are referring to in the supplementary parts list, but in the original Gr4 hand written part list for the Gr4 program that contain all the parts the factory tested and ended up using (that I coincidently am in possession of) they list a R4575 Holley 1050 dominator, that I think was used on the first Gr4s (see picture)?

They do not list the carp for the Gr3s, but they refer to the 390 HP K625J Boss 351 engine for some applications (likely Gr3??) and of course the 520 HP (Bud Moore) engine for the gr4? (see picture)

Hi Kristian, very cool. Great info. And I think you are right about the K625J, there are plenty of references on the internet to that being in the 1971 351 Boss Mustang. So maybe it used the same carb too in the Pantera GR3.

Cheers, Tim.

Hi Tim, I still have what I presume is the original Holley for my GR3 at home. I will have a look when I get to it and perhaps read some numbers off. Give me a couple of weeks........

Sounds great, many thanks! cheers Tim

a looong while back, there was a road test of a Gr-3 Pantera by Peter Revson reported in a car magazine. In the story Revson called out the particular Holley used. I think George Pence also mentioned which one it was in one of his 'stickys' on this site- which I can no longer access.

Where can I get that Blade spoiler  for that Grp4 recreation  your building, I too am running  a belt Drive a Danny B unit and Ingles electronic  FI that look like webbers,Does anyone  have pictures  of the 2 different  types of Revson front spoilers?

I don't store photos but they're in the older threads. The original Revson spoiler is curvaceous and is level with the bottom of the original nose sheet metal. The later one has a small splitter molded into its shape. Never tried it, have no idea how it works. The ground clearance looks quite close to the original. As I said in the previous post, Larry Stock's Pantera Parts Connection in NV has all those spoilers and might even have shots on his comprehensive web site.

You can't buy that spoiler anywhere.

It is a one-off that I made in 1,5 mm aluminum. It was made as a repica of the early Gr4 1972-73 gr4 racers from studying period correct pictures.

It's actually a 3-piece design that's riveted together in the center - the thinking being, that while racing the car, damaged pieces of the spoiler can easily be replaced.

I actually made another for a bloke in Germany, but even then, I can't guarantee that it will fit other cars than mine, as the placement of the flares may vary from car to car.

It's also designed to work with/wrap around the oilcooler, so running the spoiler w/o the cooler will look odd.

Kristian