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Vehicle Restoration
Specifications
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Since 1988, EPS has restored all or part of 19 cars for Vintage Racing.
These consist of R & S model Shelbys, K Mustangs, and Falcon Sprints.
Following are the range of specifications that cover these cars. These cars meet the 1967 SCCA General Competition Rules and Production Car Specifications for GT350 Shelby or A Sedan and FIA Homologation papers for sedans.
Many improvements have been made since we started with GT350R R103 in 1965.
Over this 36-year period, these improvements have been made a little bit at a time until we got it right. Sometimes, three steps forward to two steps backward, in the early days. We have some twisted parts on the windowsill that came from that period.
We are doing much better now, thank you!
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-SIZE: All have been standard to .040 over bore 289cid. The maximum allowed is .047 over bore.
-CRANKS have varied from HiPo cast to steel. Stroke is 2.87 inches.
-BALANCE has been both external & internal.
-CYLINDER HEADS are 60’s cast iron Street with 1.94 intake& 1.6 exhaust valve diameter.
-BLOCKS have been 2 bolt & 4 bolt 60’s cast iron.
-PISTONS are custom designed by Walt to fit particular heads.
-COMPRESSION RATIOS: While up to 13.7/1 has been used, 11.5/ to 11.8/1 have been used recently with great success.
-INTAKE MANIFOLD: We use an original Shelby dual plane Cobra manifold or an accurate Cobra reproduction.
-EXHAUST SYSTEMS: The Shelbys & Mustangs use Hooker comp or super comps. The Falcons require a special comp header because of clearance. Two chamber Flowmaster mufflers have proven to provide equal to or more horsepower than open exhaust, while dropping the noise level considerably.
-PULLEYS: We manufacture our own aluminum pulleys. The crank pulley diameter is 60% of stock. The alternator pulley is increased to about 6nch diameter. These slow down the stock water pump providing improved cooling. The alternator is slowed down to minimize failure at high RPM and reduce horsepower drain on engine.
-HORSEPOWER: The horsepower has increased throughout the years from 378 in 1988 up to 455 now with a flat tappet cam. These latest figures are with the 11.8/1 compression ratio piston configuration. Development continues. These are peak power or bar room horsepower figures. What is really important is the broad power band that we build into the engines. The key is to make maximum power over the operating RPM range of the motor. The engine dynamometer, which should be completed in December 2001, will be a considerable asset.
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-FLYWHEEL: Most of the flywheels are aluminum with steel contact surface, which is OK under the rules. They are original diameter. Most are 157 ring gear teeth.
-CLUTCH: We use clutch discs & flywheels of the required stock diameter. A diaphragm pressure plate and a 6-pad disc with no springs is used. Triple disc small diameter clutches are illegal under 1967 rules. Our clutches never seem to wear out.
-THROW OUT BEARING: It is just a stock high performance unit. It runs forever.
-LINKAGE: The linkage is original 1966 type that is reinforced throughout.
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-While the Shelbys originally came with the aluminum and cast iron Borg Warner T-10 and the K Mustangs with the cast iron Ford close ratio top loader, all our cars have run the old Ford close ratio top loader. Minor modifications are done to improve reliability. The old T-10 transmissions have not proven reliable after restoration.
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-DRIVE SHAFT: We never use the old ones. We have new steel units made with a heavy spline yoke in the front and a heavy duty joint in the rear requiring a special differential input yoke. We have not found the aluminum drive shaft, while legal, to be a substantial advantage or cost effective.
-DIFFERENTIAL: The 9 inch differentials are generally what came with the car. They are overhauled and fitted with an original type Detroit locker. We have never had a failure, so don’t require nodular, etc. Ratios used are 4:11, 4:33, 4:56, 4.86, 5:14, and 5:42. On cars that have only one unit, we use a 4:11. These cars use 1st, 2nd & 3rd gears on short tracks and 2nd 3rd & 4th on long tracks. They are generally lower horsepower vehicles with a lower max RPM limit.
-DIFFERENTIAL HOUSINGS: Our housings are rewelded all over. Most are narrowed about 3/4 inch on each side to allow legal wheel track and more tire clearance. The panhard rod, override brackets, & narrowed spring perches are installed. Then the housing is straightened and toe and camber added.
-AXLES: We never use original axles. We have heavy duty ones made to our specification with heavy-duty bearings. They still fit the original Ford small bearing housing end. The 1965 & 66 ones are 28 spline and the 1967 are either 28 or 31 spline.
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-CONTROL ARMS: By early 1989, we realized that there would have to be changes in the front suspension to properly utilize the new radial & bias ply tires in use. The 67 rules dictated that we had to stay with the original parts, but they could be modified as long as they could be identified as original. They are changed so as to provide optimum alignment range for both types of tires. Since the rules don’t allow the use of spherical bearings in the basic suspension parts, we use poly bushings. For long life of the bushings, the set up has no bushing bind at proper alignment. An added bonus was essentially zero bump steer over the vertical & roll range of the front suspension. No mod was required to standard or HD stock spindles.
-STRUT RODS: We wanted to use the upper control arm adjusting shims only for camber adjustment. In order to get the necessary caster; we went to the 1967 adjustable strut rod. The threads are lengthened to get better range and a slight bend is used to remove binding. Since most of the dynamic loading on the strut rod is unidirectional, and we virtually eliminate binding. The poly bushings are lasting many years.
-FRONT SWAY BAR: We found the original Shelby bar to be just fine for our set up. So far, we have not used the adjustable link pins. They just are needed. We may take another look at them later. They are free under the rules, but I think they are stretching the vintage spirit just a little. Sorry I am such a prude.
-FRONT SPRINGS: We have been using the same front springs since 1988. We have insulators for them and cut them slightly for some applications.
-SHOCKS: The same Koni adjustable shocks have been used since the 60’s when they came on Shelbys. We did use expensive double adjustable in the late 60’s Trans Am, but not now.
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-REAR LEAF SPRINGS: We provide two rates of leaf springs. The stronger ones are used on lower horsepower cars. Yep, that’s correct. The springs are 3/4inch narrower than stock 2 1/2in and sit about flat in the car on purpose. This width allows more tire clearance and less torsional resistance. Leaf design is a little different also. No reverse eye either, too much stress on material. We have a mounting kit that includes front and rear bushings, bolts, shackles and two very trick, (oh excuse the expression), little offset adaptors. These are used to mount narrow springs on stock housings. They also allow adjusting axle location slightly for & aft and side-to-side to correct for variations in the chassis. I guess they could also be used to put a little steer in for essentially one-direction turn tracks, like roundy round. The spacers in the mounting kit also allow the spring to be moved in & out and the complete housing to be offset to one side. We have never done it, but it sounds trick. There I go with that word again. That was suggested before we went to Lime Rock. Per the rules, the springs are mounted in the factory location and by original method.
-PANHARD ROD: Our design panhard rod assembly has been updated a number of times since 1966 to improve roll center and spherical bearing life. It has the greatest possible length and includes a bar from the lower part of the frame bracket to the opposite subframe. This Bolis bar has stopped the floor cracking that we experienced in 1988 & 89.
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-OVERRIDE ASSEMBLY: Our first design improvement from 1966 was in early 1989. It was a shorter solid override bar assembly to match the dynamic forward pivot point of the springs and reduce binding. Later in 1989, we went to the system where the bar came forward to a one sided vertical teeter totter which then had a horizontal shock at the top connected to a point back on the floor over the axle. This allows a cheap horizontal shock to do a big job controlling both vibration and wrap up. While this system has remained the same basic configuration since 1989, the design has been up graded several times to improve wear life. Now, like the panhard assembly, it is virtually bullet proof. It sure does a great job of tuning with our narrow springs.
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-STEERING BOX: We use the original 16/1 HiPo or power steering box. We have to overhaul most all of them.
-IDLER & PITMAN ARMS: These are the longer Shelby types. We like the quicker steering. A little tough moving around the pits with my tired old arms. We ran bearings in the idler arm in a few cars, and then went back to stock. "If it ain’t broke, don’t fix it."
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-The Shelbys run the original Mustang brakes as required per the 1967 PCS. They are 11.3-inch diameter front rotors with 4-piston caliper and 10 X 2 1/12 drums in the rear. We have our own front and rear cooling system first used on R103 in the 60’s.
The same brakes are used on the Falcons.
-The Mustangs can run the same brakes as the Shelbys. Under the FIA & SCCA papers, they can also run the 60’s T Bird/Lincoln front 11.96 inch diameter rotors and 11 X 2 drum brakes in the rear. We have found the 11-inch rear brakes unnecessary and too heavy, so we run the same 10 X 2 ½ brakes as the Shelbys.
-We have developed a combination of front pads & rear shoes that provide the proper balance when used with our various master cylinders and wheel cylinders.
-Some cars have proportioning valves and some don’t.
-Brakes are all a matter of balance. But we try to get as much out of the rear drum brakes as can be safely done.
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-FUEL CELL: We use only ATL cells. We like their quality control. Most of the cells have been steel 15 gallon. We have done a few in aluminum. And we are about to do one with a 12-gallon capacity. They have dual pickups and a vent fitting with tip over valve. We fabricate a mounting bracket that drops in original Mustang, Shelby or Falcon opening. All are the same. On this mount are two Holley low-pressure fuel pumps. Each pickup feeds a pump and the outputs of the two pumps are tied together. Filters are installed ahead of each pump. This plumbing allows fuel to be pumped even when cornering with a near dry tank. One pump pumps air and the other fuel. We fill to about 8 gallons and top off after about every session. 6.08 pounds per gallon, remember.Weight is everything.
-FUEL LINES: All fuel lines are –06 Aeroquip, including the line up to the front. This line is routed up the right side through the right fender well and into the engine compartment just ahead of the spring housing. The fuel pressure regulator is mounted at that location. It is normally set to about 5 lbs. The output of the regulator feeds both ends of the carb through a divider at the carb. A return line is not used
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-CARBURETORS: Chip has reworked the Holley 1-196 & 80145 600cfm vacuum secondary units. He may be called Dr. Weber, but he also knows the Holleys very well. We offer three stages of these carbs. These carburetors even work great on engines up to 427 & 428 cid race motors. The race carbs have the choke housing air horn removed. A plastic velocity stack is fitted to the top of the carb. We prejet the carbs and then do final jetting on the chassis dyno. An EGT (Exhaust Gas Temperature) reading is taken from the gauge in the car.
The EGT reading is then used to jet the carb for barometric pressure changes due to weather and/or altitude. We are testing an even smaller stock carb with annular discharge rings that we think will provide even better punch out of the corners. Most all cars run a single carb. FIA papers allow some Mustang & Cougar models to run dual carbs. When done, it is for looks only, for we have found this set up to be a disadvantage for best engine performance. Both of the above mentioned carburetors are now out of production at Holley, so, we are testing a new 600 cfm Holley that we expect to have available in the near future in the three stages.
-SAFETY CIRCUIT: This circuit protects the engine is case of oil pressure failure by shutting off the fuel pumps with loss of oil pressure.
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-WATER PUMP: Now this is really trick. It is a NAPA rebuilt original early type pot metal standard pump. We do a little to it but not much. Seven pounds saved here over later ones. Never had one go bad, never. But we do carry a spare. We keep loaning it out to other people. When they see what it is, they always give it back when they replace theirs.
-THERMOSTAT: None used. We experiment with restrictors to get the correct backpressure.
-HOSES: We start with the original type woven rubber hoses and do a little cut and fit. We use a steel tube to come across from the left side to go back into the pump. Several cars done by us have water to oil coolers in place of the pipe
-RADIATOR: We started with the old Galaxy vertical tube brass radiator. But after Keith, our Falcon guy, showed us a photo of a Falcon running with aluminum cross flow radiator in the early 60’s we succumbed. The radiator contains a thermal fan control switch.
-OIL COOLING: For best cooling the oil is precooled by a Modine air to oil cooler mounted behind the left or cool side of the radiator. Then the oil is passed through the cooler in the outlet tank of the radiator. Precooling the oil helps to reduce the cooling load on the radiator and allows the water and oil temperatures to be fairly close. –12 lines are used for oil lines. The oil is passed through a remote oil filter mounted to the left engine compartment panel.
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-BATTERY: A cheap 18-lb. garden tractor battery is mounted in the right rear corner of the trunk. We tried a “trick” race battery. That was a real mistake. #2 battery cable is used for all the battery and starter lines. An Anderson connector is mounted in the rear body shell behind the battery for plugging in a mating jumper cable.
We rarely need it.
-STARTER SOLENOID: A standard Ford solenoid is mounted on the right kick panel. The wiring to the starter includes a solenoid primary wire to use with starters that include a solenoid.
-RIGHT KICK PANEL: The right kick panel is the main electrical distribution center for the car electrical. It can contain MSD 6AL and shift light module or rev limiter module and shift light module when just points or Perlux/Pertronix are used.
-MASTER SWITCH: A 4 terminal master switch is used to switch primary battery cable and an alternator field relay. This assures that the engine dies and won’t run on the alternator if the master switch is turned off with the ignition on.
-ENGINE COMPARTMENT PANEL: It provides a one connector feed for the entire engine electrical. It also provides wiring for fan and racing transponder and contains the voltage regulator.
-BUMP SWITCH: The bump switch is mounted in the engine compartment on the firewall and allows bumping over the engine for valve adjustment without the engine firing.
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-CONTROL BOX: This well styled aluminum box is mounted on the center drive shaft hump next to the driver. It has the ignition key switch, prime & start switch, fan control switch, an accessory switch and a light that tells when fan is on.
-INSTRUMENT PANEL: This black crackle panel is based on the Shelby R model panel but has no speedometer. It has a large 2 inch red shift light, oil pressure, oil temperature, water temperature, fuel pressure and battery voltage gauges. It also has a small oil pressure light and a charge indicator. A tachometer is placed in the center.
-CENTER GAUGE PANEL: This panel placed in the center over the radio opening contains the dual EGT gauge and a large 2-inch low oil pressure red warning light.
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-PREP: The bodies are stripped, dipped, straightened; stitch & seam welded and have a cage installed before painting. Various brackets are also welded on to the body before painting.
-MATERIAL: The Mustangs remain all original. The Shelbys have plastic front valence and aluminum R model type side roof panels added. A plastic R model type hood is added if not original. The Falcons, so far, have been all original metal. But we look forward to start installing fiberglass reinforced plastic panels as listed in the 1964 FIA homologation papers.
-WINDOWS: While some clubs allow plastic, like Lexan, to be substituted for glass, the SCCA rules require glass all around in the A Sedans. In these, the side window functions must be working. In the Shelby GT350, the windshield & rear window may be made of plastic. We use Lexan for the windshield. Under SCCA rules, the side windows may be removed completely. Oh yes, Lexan was available in the 60’s.
-WHEELS: While 1967 FIA papers allow Mustangs to run 15 X 9 inch wheels, RMVR allows all A Sedans to run 8 inch, and most all Mustangs comply with this size.
The Shelby GT3350, per the 1966 and later SCCA rules, runs 15 X 8 ½ wheels.
-WEIGHT: Dry, most of our Shelbys, Mustangs And Falcons weigh between 2575 lbs. & 2800lbs.
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If all this sounds a little conservative, check our race results!
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For more information:
E.P.S., Inc.
P.O. Box 1043
Evergreen, CO 80437-1043 US
Email: epswalth@aol.com
303-674-6017
© Copyright 2008 This website was created by SNetSolutions
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