tech tips


Now that Castrol has discontinued the long recommended 80W90 Hypoy GL-4 gear oil, Now what oil do we use in our Pantera Transaxles and why?

There are many discussions about what is the proper oil to use in the Pantera ZF 5DS-25/2 transaxle. Basically today there are 2 oils, a Castrol 80W90 LS (Limited Slip) and the Redline 75/90 NS, available from Pantera Parts Connection (1-800-DeTomaso (338-6627)) now, so which should we choose?

Shaft Assembly
The answer is complicated because The ZF gearbox is not just a simple Transmission Gear only type design so a lubricant does indeed need to satisfy the requirements of a limited slip differential ... plus the ring and pinion gears, bearings of all types, transmission gears and the synchronizer rings. The lubricant must also be non-corrosive to steel, aluminum, and "yellow' metals (i.e. copper, brass or bronze) especially if your ZF has these brass synchro rings.

ZF's recommended viscosity was SAE 80 n 1972 or SAE 80W90 stated in today's modern lubricant technology. The synchronizers, brass/bronze parts and limited slip differential within the gearbox has traditionally meant lubricants rated API GL-4 are the best lubricants for the ZF. GL-4 lubricants are medium load lubricants in which the additive package has been specifically formulated to meet the requirements of limited slip differentials and synchronizer rings, while being non-corrosive to aluminum and yellow metals. API GL-4 lubricants were common lubricants for transmissions and transaxles. The Castrol 80W90 Hypoy Gear Oil (GL-4) was among the most favored lubricants ZF originally recommended to Ford but Castrol has now discontinued this GL-4 grade since 2008. Now what?

Wheel & Pinion
RBT states that they recommend that you use an API GL-4 rated gear oil. The RBT/ZF transaxle designs use the highly efficient Spiral Bevel style crown wheel and pinion set. There is no Hypoid offset in this type of gearing; hence, there is no longitudinal sliding along the face width of the tooth. Therefore, the additional friction modifiers used in GL-5 type oils are not required. These friction modifiers, required to reduce heat and prevent scoring on Hypoid gear sets, can have an adverse effect on the function of the transaxle synchronizers, for example, requiring greater shift effort. But all the oils available today are GL-5 rated so they need to be specially blended and balanced with friction modifiers.

Today if you have Brass Syncro Rings installed in your ZF we must recommend to put you into a newer formulation Friction Modified Synthetic like a RedLine 75W90 NS GL-5 LS, available from the Pantera Parts Connection, for use in differentials with the Spiral Bevel style crown wheel and pinion set found in the ZF or RBT Transaxle. This oil is designed to help slow synchro's for easier shifting across a broad temperature range. It contains the extra pressure additives, but lacks friction modifiers to balance slipperiness. This oil incorporates low sulfur content for Improved copper corrosion protection to prolong synchro life. This Synthetic oil helps with Limited Slip lock up and can be additionally tuned with Redline limited slip Friction Modifier if limited slip clutch chatter becomes evident.

Syncro Ring
Standard GL-5 lubricants found in most auto parts stores have a higher load rating than GL-4 lubricants, but the GL-5 additive package is usually not compatible with limited slip differentials or Brass synchronizer rings; the GL-5 additive package is usually corrosive to other yellow metals too. However, some API GL-5 lubricants contain friction modifying additives specifically added for limited slip differential usage (the label should specify it has a modified API rating such as GL-5+ or GL-5-LS). API GL-5 lubricants are common lubricants for axles that are independent from the transmission. Even when modified for limited slip differentials GL-5 lubricants are not usually considered suitable for the synchronizer rings & yellow metals in a transmission or transaxle. So use of these standard GL-5 oils is not recommended for long term use.

However, in the case of Castrol's current non synthetic 80W90 Hypoy Gear Oil (which is rated API GL-5 LS) available from Pantera Parts Connection, which has been Transaxle builder RBT's favored recommendation which indicates to me it must be OK for the ZF's for half the cost of the Redline synthetic oil, at least when using the RBT Cast Iron Synchro's that RBT Sells and uses in their ZF/RBT rebuilds. Beware because ZF also produces Brass Synchro's for the ZF-5DS-25/2 that some rebuilders use that are less expensive and will work fine as long as you use the Synthetic Redline oil described above.
That is why every question is answered and qualified with another question. How fast do you want to go, and for how long?


HOT TRICK - 25HP Induction System!


Quick Fuel Carburetor
Do feel like your dragging an anchor. You can feel surges of power and then it sort of plateaus out. We found that the pantera gains low end torque and 12 horse power to the rear wheels by replacing just the intake manifold. This gain is because back in the late 60's bigger was better. Ford designed the 351 Cleveland to run NASCAR. They basically put big block heads on a small block motor. This was fine at 7500 RPM, but we do not run at that speed unless we spend big bucks on the motor to spin that fast and stay together. They have later found that bigger is not necessarily better in this case because the atomized fuel droplets are flowing so slowly through the induction system that they actually fall out of suspension. This produces bigger droplets which leads to incomplete combustion and loss of power.

The Edelbrock performer manifold reduces the size of the plenum runners which increases the rate of flow, which keeps the fuel in suspension better and produces the extra HP and a lot more low end torque. In a Pantera low end torque is what really sets this car apart from other higher priced exotics. There are lots of improvements that have been made on the Cleveland motor in regards to increasing torque and power but this is the simplest and by far the biggest bang for the dollar.

By doing a number of chassis dyno tests we found that by just changing the original Autolite carburetor to a new smog legal 600 Holly that we picked up 12 house power. This is again accomplished through better fuel atomization which the Holly's do much better. This requires intack manifold machining since the butterflies don't line up with the ports. Replacing the manifold with a new Edelbrock is surely the best solution and results in a combined 25 horsepower increase. This is surely the best single power/economy improvement you can make to the Pantera.


Part# Description List Price Sale Price
08407E 2V Edlebrock intake manifold 228.95 195.00
05037P 4V Edlebrock intake manifold 228.95 195.00
08406C Smog Legal Holly 600 395.00 350.00

HOT TRICK - Keeping the Deck-Lid off Your Head

First question I usually hear is if we stock original type Deck-Lid support shocks? All I can find are these little things.... They just can't work as well. Wrong bunko. These little gas support strut shocks work as good as before. They are just like everything else in this world they are getting smaller, lighter, and more powerful. But for you original affectionsotto's I'm sorry to say.. I can not make the big original shocks reappear.

Pantera Parts Connection does have two ratings of Deck Lid Shocks available. Some other vendors have marketed a shock that certainly hold up your lid and when warmed up to a hot summers afternoon engine temperature literally warps your deck lid up from its hinges. This problem is getting common and is not easily corrected (we sell new deck lids too for only about $3500.00). You see engine heat (emanating from just below where your support shocks are mounted) will increase the pressures inside your support shock substantially. You may notice that your deck lid stays up while driving around on that warm sunny August wine tour, but you can't keep it up at all when Christmas shopping in the snow (unless your name is Bill Clinton). That is if your dumb enough to go out in the snow in a Pantera, and if you are get me something too....:-)

Pantera Parts Connection came up with two shock pressures, one is on the weaker side we call the '18126P'(@ $42.00 each) Standard deck lid, and stronger version we call the '18126W' (@ $42.00 each) for Wing equipped version. The 18126P may still not hold up your lid in the dead of winter but I have seen too many warped deck lids to risk not giving you a choice. If all else fails or you are too cheap to buy a pair of these fine upgraded Support Shocks, we also now are offering a fine telescoping aluminum prop (#18126S @ $25.00 each) with rubber tips. So now you have no excuse for picking up something nice for that special someone for Christmas.

When your showing your engine to your friends, you don't look like a a hacker mechanic. It also means you won't warp your deck by over sizing the shocks. Oh, and don't forget the reduced doctor bills and scaring of the head from all those bumps and scrapes.


Part# Description List Price Sale Price
18126P Deck lid shock 74.00 42.00
18126W Deck lid shock (Wing) 74.00 42.00
18126S Telescoping Support Tube (aluminum) 25.00 25.00

HOT TRICK - The PPC Custom Holly Double Pumper: 20 Additional Horse Power!

The Holly Carburetor has proven to be a huge improvement over the original Autolite with better flow and fuel atomization. Larry Stock of the Pantera Parts Connection has found that the ultimate platform for the 351 Cleveland is the Holly 4778 4150 better known as the 700 double pumper. He tested all types of Holly double pumpers including the favored 750, and many recommended vacuum secondary 4150 model's including the 600's and the 735 CFM 428 Cobra Jet carburetors. He choose the 4778 because it seemed to perform out of the box the best. This model also seemed to respond to tuning much better than the others tested. In tuning with a computerized G meter instrument he was able to tune out the flat spots, the sags and bogs. He then, once satisfied that the in car performance characteristics were optimized, put the car on a chassis dyno at a standard temperature and pressure at sea level and jetted the carburetor. The "PPC Special 700 Double Pumper" is ready to go so you don't have to make over 35 separate adjustments and waste over a thousand of dollars in custom Holy parts.

Quick Fuel Carburetor
We put this carburetor on another stock engine using a chassis dyno. Took readings with his 750 Holly double Pumper and then replaced it with the PPC special 700 Double Pumper. We see 22 Horsepower increase with no other modifications. This carburetor on this otherwise stock Pantera unwittingly passed a California Smog inspection with a little timing rollback and got 17MPG on a trip to the annual POCA Fun rally. We put the PPC specially modified 700 Double Pumper on another slightly modified Pantera motor and found a similar 17 horsepower increase. Customers comment that the car seems to respond as if unleashed. One customer said that his buddy spent over 6000.00 on a fuel injection system, but "He still couldn't pull me!" Pantera Parts is so confident in these Holly built units that they offer a money back guarantee if not 72% satisfied... Now you just can't beat that now can you !!! OK were just kidding really 100% or your money back !!!


Part# Description List Price
08406P PPC 700 Double Pumper 750.00

HOT TRICK - High Performance Pedal Action!

PThe Clutch system in a stock Pantera is barely adequate to engage and disengage the throwout bearing. In many instances the throwout bearing remains engaged causing a limited part life. Another symptom is the clutch does not fully engage reducing performance. Finally, during shifting it places additional load on the already weak syncro's in the transaxel.

Replace your old slave cylinder with the PPC Long Throw Slave Cylinder made from Stainless Steel. The slightly smaller bore will increase the slave cylinder piston travel allowing the proper free play setting.

Aside from solving the problems of throwout, clutch engagement and syncro problems, the stainless steel construction will not rust and pit if you forget to regularly change your fluid. Of course you know that the brake fluid used in these systems asorbs water and will rust regular iron slave cylinders.

PPC also offers these Stainless Steel Slave Cylinders in the standard bore size for the same original specifications with the benefits of stainless steel. Of course Pantera Parts Connection offers original DeTomaso replacement Slave Cylinders also for the purest.

Slave Cylinder
Part# Description List Price Sale Price
05037L Clutch slave cylinder Long Throw (stainless) 175.00 150.00
05037P Clutch slave cylinder stock Throw (stainless) Purest stock part 175.00 150.00
05037A Clutch slave cylinder stock OEM (iron) 82.51 75.00

HOT TRICK - Adding 7/8" Rear Sway Bar!

Adds .14G's on a skidpad with a stock bodied car, no other changes needed. Complete System For Under $300. Feel the difference the first time you do 150 on a freeway off ramp!

Parts Needed:

Sway Bar
Description Part#
Sway Bar (Rear) 7/8 02121C
Sway Bar (Rear) 7/8" Chrome 02121P
Aluminum, sway bar bracket 02012N
Bushing, sway bar mount 02019P

HOT TRICK - Tires Rated for 150+ MPH!

Going over 130 MPH on a H rated tires, well you shouldn't, because H rated tires are only safe up to 130 MPH. You should really be running with Z rated tires with the 17" Kinesis rims.

The latest technology Z rated ((150+ mph) 245-40/17 (F) & 335-35/17 (R)) rubber mounted on PPC / DeTomaso appointed Kinesis 17¾ X 13¾(R) & 17¾ X 9¾ (F) Wheels with the correct Pantera offsets so they fit under your stock bodied car. If you want pure performance we can mount these with DOT HOOSIER autocross or Road Race real sticky rubber. WORK EM HARD AND MAKE EM TURN

If you like your car L - O - W then you might need to remove or otherwise modify your windshield wiper motor cover....who uses that stuff anyway. Did you know that the closest tire fit is on the front of Pantera's. The shorter the tire the wider you can go. These 245-40 / 17 tires are shorter than the old usual 225-50/15 or newer 235-45/16 tires. It has been rumored about that somebody actually has fit 255-35/17's in their front fenders, try this before you buy it though or only buy one first.


Part# Description List Sale
01027M Wheel,K-10 17 X 9 Polished Center 900 780
01027N Wheel,K-10 17 X 13 Polished Center 935 810
01027W Wheel,K-20 17 X 9 Painted Center 850 730
01027X Wheel,K-20 17 X 13 Painted Center 885 760
01027Y Wheel,K-20 17 X 9 Standard Center 800 680
01027Z Wheel,K-20 17 X 13 Standard Center 835 710
01028B Wheel,K-5 17 X 9 Polished Center 900 780
01028C Wheel,K-5 17 X 13 Polished Center 935 810
01028D Wheel,K-5 17 X 9 Painted Center 850 730
01028E Wheel,K-5 17 X 13 Painted Center 885 760
01028F Wheel,K-5 17 X 9 Standard Center 800 680
01028G Wheel,K-5 17 X 13 Standard Center 835 710
28001K Tire , Hoosier 245/40-17 225 200
28001L Tire , Hoosier 315/35-17 285 250
28001M Tire, Yoko 235/40-17 250 225
28001N Tire, Yoko/Dunlop/Bdgstn 315/35-17 307 292
28001O Tire, Yoko/Dunlop/Bdgstn 245/40-17 250 225
28001P Tire, Yoko/Dunlop/Bdgstn 335/35-17 350 333

PCNC DYNO DAY - Dyno Day and Horsepower Clinic - by Mike Drew

Dyno Run
The Pantera Club of Northern California gathered at Rockwell Engineering in Santa Clara for the Second Annual PCNC Dyno Day . Charlie Rockwell graciously volunteered his time and the use of his facilities to enable us to diagnose how our cars run. Larry Stock orchestrated the event, and provided the barbecue and charcoal for the obligatory burger burn.

This event had two distinct purposes. PCNC members were able to have their cars evaluated on the chassis dynamometer, to determine exactly how much horsepower was being produced. As an additional bonus, owners could see what the levels of emissions were, and from that, determine if the car was jetted properly, had an ignition problem, etc. Along with testing members' cars, the Horsepower Clinic portion of the day centered around a test mule Pantera. The intent was to start out with a bone-stock car, and gradually make modifications (i.e., carburetor and manifold swaps)' with the hope of discovering exactly what kind of gain (if any) is available from these various components.

The original scenario involved Larry Stock's car as the mule, but as you know, he grenaded his motor at Las Vegas, and his new motor would no longer be stock. Fortunately, Jim Kuehne stepped in and volunteered the use of his still-stock car. The plan of attack called for Jim's car to be tested, then pulled off the Dyno, and while a modification was being performed, another member's car could be tested, thereby maximizing Dyno time.

By the end of the day, there were a lot of lessons learned, and more than a few egos deflated as here-to-fore-unknown engine woes became apparent to all watching the goings-on. There was also a new undisputed king-of-the-hill in the normally aspirated horsepower war.

The member's cars horsepower numbers are reproduced in the table below. To provide a general description of a non-stock motor, "salsa" guidelines are used. Carburetors are all Holley, with either Manual or Vacuum secondaries. As a rough estimate, engine horsepower can be determined by multiplying rear-wheel horsepower by a factor of 1.26.

Intake Stock ? Stock 72 Performer Torker Performer Performer Performer Stock
Carb Stock ? 650 Man 750 Vac 750 Vac 750 Vac 750 Man ??? Vac 600 Vac

3000 150 145 148 145 145 141 150 NA
4000 198 190 200 189 199 235 211 200
5000 200 200 237 197 233 278 250 229
5500 NA NA 236 NA 234 295 257 226 NAs
6000 NA NA NA NA NA 298 216 NA

Most cars that weren't fully tested were simply running to poorly to make continued testing worthwhile, or even physically possible. Lee Scales' Pantera initially had the coil hooked up incorrectly and even after that was fixed. The car appeared to be suffering from fuel starvation, and would not pull any sort of heavy load. Hal Harter had a bad spark plug wire, Joel Gust had intermittent ignition problems, and Ken Levin fouled a plug. Roy Hanshe (whose data I didn't record) couldn't reach more than 4500 RPM, as his engine would cut out completely, and the car would backfire most impressively. The interesting thing is, Roy was the only person who was aware he had any sort of problem at all, as during normal street driving, these sorts of problems are usually masked. It all proves the value and importance of Dyno-testing your engine. Petar Harks had his own set of problems. He has a brand new motor, which incorporates port plates (which are all the rage these days). The problem is, he is using an Edelbrock Torker manifold, which (at least on the 351C model), is designed for anything but torque production. In fact, it is a high rpm, high horsepower intake, and when coupled with this restrictor plates, the result is complete havoc in the combustion chamber. He tried three different carburetors (which worked fine on the other cars), and the car ran so rich that the meter was pegged, and the sound of backfires filled the air.

Ted Lawson was one of the happier members after his car was tested. His Hall-built motor produced the second highest horsepower rating (257 hp @ 5500 rpm, but the powerband fell off a cliff shortly afterwards, dropping to 216 hp @ 6000 rpm. Charlie Rockwell determined that the primary jets were two sizes too small, and the secondaries were too rich. Also, the car had a consistant backfire at idle, which everyone was at a loss to explain.

The undisputed champ of the day was Roger Sharp. His motor even sounded meaner than the other cars when he drove in onto the Dyno. He has recently installed a big buck solid lifter powerplant, and the results speak for themselves. His car was producing as much horsepower at 4000 rpm as most others were producing at 6000 rpm. Is final result was just shy of 300 horsepower, which is a lot in any body's book. Further more, the motor was belching clouds of black smoke from the exhaust (he joked that birds were going to start falling out of the sky at any minute), as it was much too rich. Once properly dialed in, it is likely to produce even more horsepower!

Now while these numbers are pleasant to look at, and provide their owners with a reference point for further modifications and tuning, they really don't provide much objective data. For truly informative (as opposed o merely descriptive) results, a standard had to be established, against which changes would then be measured. To that end, we turned to the mule.

Unfortunately, Lucas, the Prince of darkness, reared his ugly head, and after only the fourth trial, Jim's Pantera stopped stone cold dead at 5000 rpm. The silence was truly deafening. A bit of tinkering, coupled with some appropriate lanquage, got the car started again, but it quit again shortly thereafter, and smoke started to waft up from the passenger side seatbelt retractor. So the car was pushed off the Dyno, and the ratchets started to whir, and before you knew it, half the interior was lying on the ground. It turns out that a wire leading to the automatic choke had grounded out, causing a short and subsequent electrical fire. The charred wire was removed, and a new wire spliced into the harness, but so much time had gone by that it was impossible to continue testing. As a consequence, only four configurations were tested. The results are as follows:

Jim's Dyno Run
INTAKE Stock Stock Performer Performer
CARB Stock 600 Vac 600 Vac 600 Vac(Econline)

3000 159 162 167 169
4500 191 202 206 210
5000 205 205 232 232
5500 198 198 230 230

As can be seen, real progress was being made. The switch to a Holley 600 cfm carburetor accounted for an increase of 22 horsepower, and the Edelbrock intake gave another 10 horse4power. It is anybody's guess to exactly how far thing could have gone had we not run of time. However, we now have an idea of what is in store for us next year! Some club members took Charlie Rockwell and his wife out to dinner to express our appreciation for all his efforts, and a few members have returned to have their cars tuned. After seeing all problems that supposedly well sorted cars had, it seems that a visit to Rockwell Engineering (especially at a smog check time) for a full diagnostic and Dynotune is virtually a mandatory procedure!