At this point in the construction of your Cobra replica, you’ve no doubt come to the same conclusion we did: there’s a mind-boggling amount of details to building a kit car. If you’re like us, no matter how far along you are in the project, there are many times when it seems as though the car will never be finished.
This Tech Tip is From the Full Book, HOW TO BUILD COBRA KIT CARS + BUYING USED. For a comprehensive guide on this entire subject you can visit this link:
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Consider the mountain of work before us in this chapter. The reality is that every little bit of work on our FFR Mk4 roadster is done painstakingly, with attention to detail and with pride. With this approach, there is no small task. They’re all important, because we are the ones who are going to be driving, enjoying, and showing our FFR Mk4 Cobra roadster replica. We’re sure you’re taking the same sort of path with your replica’s construction, whether it’s a Unique Motorcars 289FIA, an E.R.A. 427SC, or a Backdraft Racing Roadster that’s awaiting its drivetrain installation and final wiring hook ups.
You’ve likely heard the old adage, “The devil’s in the details.” In the construction of any replica, muscle car, or classic car, we would like to amend that statement to more positively and accurately describe the build process as, “The delight is in the details.” All these build tasks are opportunities to make our Cobra stand out from the crowd. Having a glass-half-full approach to creating a Cobra replica is preferable to being mired in the seemingly endless amount of work that a build entails.
Especially when they’re ceramic coated, exhaust headers make quite a visual and acoustic statement in any engine bay. The Hooker headers that come with the FFR Mk4 Roadster Complete Kit scream performance, and they’re a snap to install.
Project 1: Header Installation
Step 1: Install Driver-Side Headers
Be sure to use Loctite on the supplied fasteners to help prevent an exhaust leak. The bolts do include lock washers, but we still applied Loctite to the threads. Unless you have some whiz-bang special extension for your torque wrench, you cannot use it to insure these fasteners are tight enough. Tighten them by feel, like we did.
Step 2: Torque Down Header Flange Nuts
Like the exhaust headers that go in many American muscle cars, clearance is pretty tight with the firewall. You can install and tighten some of the header fasteners from above the car. The rear bolts need to be tightened from underneath the car. Do your best to make sure that all of the fasteners are equally tight, without over-tightening them. This is especially important when threading bolts into aluminum cylinder heads, as is the case with us. Do not cross-thread those fasteners!
The Factory Five Racing Mk4 Complete Kit includes many of the required components for equipping the roadster with a clutch cable, which made our decision to install a cable clutch much easier. Several prominent FFR Cobra roadster replica builders recommended using a clutch cable, rather than hydraulic, so our decision was easy.
Project 2: Clutch-Cable Installation
Step 1: Install Clutch Cable
Installing the clutch cable presents its own challenges. The already installed clutch quadrant and the clutch cable itself, as supplied by FFR, are excellent quality. The challenge was to adapt the 90-degree-angle bracket that’s attached to the clutch cable. We could not figure out anywhere to mount the bracket that allowed us to install the clutch fork end of the clutch cable. Routing the upper end of the clutch cable is straightforward. Simply run the cable itself through the hole in the clutch cable adjuster and affix the end to the end of the quadrant. It’s a friction fit, so when you put your foot on that clutch pedal, the clutch cable end is hard against the quadrant.
Step 2: Mount Clutch-Cable Bracket
We could not find any place on the entire front part of the car to install that 90-degree clutch-cable bracket that’s permanently affixed to the clutch cable. Our clever solution? We straightened out the bracket in our vice and installed the clutch cable bracket to the Dart Pro-CNC aluminum cylinder head.
Step 3: Mount Clutch-Cable Bracket (Continued)
As with the top of the clutch cable and its installation with the clutch quadrant, the clutch cable is a friction fit with the clutch fork. Be sure to place the plastic housing of the clutch cable in the engine’s backing plate and feed the clutch cable end into the clutch fork. Don’t worry, the installation is as easy as it appears.
Step 4: Mount Clutch-Cable Bracket (Continued)
After testing the clutch pedal with our collective left feet, we realized that the clutch cable bracket was a bit too flexible for our taste. The problem: When we straightened out this 90-degree bracket to let us attach the bracket to the cylinder head, we took out some of the bracket’s tensile strength. We removed the clutch cable with its permanently affixed bracket and took the component to Warner’s Mufflers in our hometown of Oceanside, California. At Warner’s, Brett welded some metal reinforcement bars onto the back of our customized bracket. We reinstalled the clutch cable and tested the clutch pedal’s actuation to confirm that we now have a properly installed clutch pedal and clutch cable.
Step 5: Fill Engine and Transmission with Fluids
After the Hooker headers and the clutch cable were squared away, we could focus on filling the powertrain with fluids. The engine still has its break-in oil in the Moroso custom oil pan. So we backtrack farther and start with the Tremec T56 Magnum 6-speed manual transmission. If your engine needs oil, put it in now. Depending upon how large your oil sump is, you may need up to 9 quarts. The Tremec T56 Magnum 6-speed manual transmission we’re using requires Dexron III/Mercon automatic transmission fluid. Our particular setup is a brand-new Lincoln Mk8 differential and independent rear suspension system, which utilizes SAE 75W-90 full synthetic gear oil. That’s what we used. This is also a good time to pour in the coolant. We opted not to fill our cooling system just yet, because we considered making some modifications to the cooling system. You may wish to fill your system at this point.
The best time to fill the drivetrain with the appropriate gear oils and fluids is when the transmission and the differential can be most easily accessed, which is before the body is put on the chassis.
Since we also installed a front shifter on the Tremec T56 Magnum 6-speed manual transmission, we removed the original shifter, installed a block-off plate, put the proper tranny fluid in, and installed the new shifter.
Project 3: Transmission Shifter Installation
Step 1: Install Shifter Relocation Kit and Fill Transmission with Fluid
The shifter relocation kit we procured from Modern Driveline is super easy to install. With the kit, you get a block-off plate for the rear Tremec 6-speed manual transmission and a slick, 6-speed shifter assembly that goes in the front shift location. Begin adding fluids at the manual transmission. We installed a front shifter in our 6-speed transmission, so we removed the front block-off plate and the rear shifter. Pouring in the Dexron III/Mercon automatic transmission fluid, nearly all 4 quarts of it for our Tremec T56, is easy with the rear shifter removed. If you’re using a different transmission, first find out how much fluid it requires and what kind of fluid you need to use. We then filled the differential up with the synthetic gear oil, being careful to fill the differential to the proper level so it wouldn’t spill out the fill hole. Using a see-through fill tube to pour the gear oil in the diff is a good way to avoid spilling the stuff.
Step 2: Install Shifter and Block-off Plate
To thoroughly seal both the block-off plate opening and the front shifter location opening, apply gasket maker to the perimeter of both openings before installing the block-off plate and the shifter. To ensure a smooth shifting Tremec T56 Magnum 6-speed manual transmission, we put a dollop of white lithium grease on the internal end of the shifter. Use the same fasteners that you removed to install the shifter and the block-off plate. Before putting this together, spread some Loctite on the bolt threads and torque these fasteners to the appropriate specification.
By all appearances, it seemed that installing the roll bar would take no time at all and be simple. Since there are three installation holes that need to be drilled through frame tubes that poke up from the trunk floor and the frame, the roll bar must be fitted before the body is installed. You then need to remove the roll bar before placing the body on the chassis.
In addition, on a FFR Mk4 chassis, these attachment tubes aren’t powdercoated; they’re raw steel. Before doing any roll-bar fitment, you need to sand the raw steel, primer, and apply Rust-Oleum gloss-black paint to prevent rust and make those roll-bar installation pipes look nice.
Project 4: Roll Bar Installation
Step 1: Paint Frame Attachment Tubes
If you’re like us and you forgot to paint these tubes before the trunk floor went in, mask off the area around the pipes to keep overspray from getting on your shiny-aluminum trunk floor and walls.
Step 2: Install Roll Bar
Just like the original 427SC Cobras, the FFR Mk4 roadster sports a roll bar that has 1½-inch-diameter tubes. Previous FFR roadsters had 2-inch-diameter tubes. We know how easy this installation looks, but it’s not so. Because the roll bar has a great chrome job, the tubes don’t fit in the just-painted installation pipes. Our trick to getting these tubes to fit was to use a brake cylinder hone, powered by our electric drill. We honed away at these three installation holes with a cutting-stone-tipped brake cylinder hone for 3 days! Also, once you have the right clearance to fit the tubes, install the back straight tube first and go in a full 2½ inches. If your roll bar is as feisty as ours, coax all three pipes far enough in their respective fitment sleeves with some firm whacks with a rubber mallet. There may be one or two expletives uttered during this process. This is understandable, given how difficult these pipes are to fit. Then fit the hoop in about 2 inches and raise the straight tube to connect with the hoop’s rear tab. After properly fitting the roll bar in the round installation sleeves, use a 1/8-inch drill bit to drill a pilot hole. Place masking tape over the area to be drilled and punch a starting divot to keep the drill bit from walking. You can also use vice-grip pliers to clamp the pipes tight. This prevents the roll bar pipe from moving inside the installation sleeve. When you’ve gone all the way through to the other side, use your 5/16-inch drill bit to put the fastener’s installation hole in the sleeve and the roll bar pipe.
Step 3: Install Roll Bar (Continued)
Repeat this same drilling procedure two more times with the sleeve/roll bar pipes and install the supplied fasteners. After the fasteners are holding the roll bar firmly, drill the rear roll bar tube that goes into the roll bar hoop’s tab. Use some masking tape and punch a starting divot, minimizing the chance that the drill bit walks. After you properly install the roll bar, step back and admire your work. You should, because you removed the roll bar in order to install the body
Remember your first days of school when you made new friends and you got your seating assignment? Ideally, all your friends surrounded you. In a Cobra replica, the driver’s and passenger’s seats are prime real estate, so installing those seats properly for maximum comfort and great driving ergonomics is crucial to successfully building your Cobra dream machine.
Factory Five Racing gives its customers several seat choices. You can select the stock seats that are the same style as the originals, but are trimmed in vinyl, as opposed to the genuine leather seats that were in the Cobras from the 1960s. You can pay a bit more and get leather seats or you can buy some modern high-backed racing seats that have the FFR logo on them. (Other replica manufacturers likely also give you choices.)
We fit our seats and found out how easy they went in the FFR Mk4 cockpit.
Project 5: Seat Installation
Step 1: Drill Mount Hole for Seat Tracks
If you want some adjustment for the driver’s seat in your Cobra replica, you have several options. If you’re building an FFR Mk4 roadster, you can order a set of seat tracks from FFR for about $80. There are also viable alternatives from companies that make components specifically for FFR cars and for other Cobra replica manufacturers. Breeze Automotive specializes in parts for FFR, while Finish Line Accessories has components for the various Cobra replica kits. Thankfully, the FFR seat tracks come with a complete packing list, all the components required for doing the job, and a thorough set of instructions. Mind you, don’t think this little installation is easy. The tools required include: jack stands, jack, Sharpie, 3/16-inch hex key, 3/16- and 5/16-inch drill bits, electric drill, 3/8-inch socket, ratchet, and a ruler. We were actually stumped on the very first instruction, which is to remove the studs from the seat tracks. Try as we might, we couldn’t get the darn things out of the tracks. So we asked our good buddy Jim Warner, owner of Warner’s Mufflers in our hometown of Oceanside, California, to remove the two studs from each seat track. After turning the seat track upside down, we marked 1/8-inch back from the side that has the square hole. As instructed, we used a 3/16-inch drill bit and then opened up the hole with a 5/16-inch drill bit. Our just-drilled 5/16-inch hole. The FFR instructions don’t show an actual photo, so this is a computer graphic. The challenge of going from a 3/16-inch to a 5/16-inch hole is being able to center the drill bit after the metal material has already been removed. We took our trusty hand file and removed the material between these two holes. If you’re using the same FFR-supplied seat tracks as we did, you are likely to do the same thing.
Step 2: Determine Mounting Location for Seat Tracks
After finishing this first hole, mark the front bolt location of the seat track 10-13/16 inches forward of the middle of the rear rectangular hole. Drill out these two front bolt holes with the 5/16-inch drill bit and install the bolts and locknuts as shown. The FFR seat-track instruction pages recommend jacking up the driver’s side of the car and placing jack stands underneath. You may as well jack up the whole car and use all four of your jack stands because we installed the passenger’s side after we finished with the driver’s side. If you’re installing seat tracks in your FFR as we did, you can appreciate the detailed drawings of the cockpit of your car. After drawing a line on the floor of the driver’s side that is 1 inch forward of the outer seatbelt mount and 13 inches towards the center of the cockpit floor, place the inside seat track with the adjustment-lever-track’s trailing point on the edge of that line and going forward. From the start of the line that you marked on the floor, measure 4 inches and put a perpendicular line on top of the line that already exists. This is the location of the outer seat track. The front bolts that hold down the seat tracks should be 1013⁄16 inches center to center from the rear seat track holes. We drilled the rear holes 4 inches in on the line for the outer seat track and 13 inches total from the start of the line (or 9 inches in from the outer-seat track hole). These 3/16-inch holes are drilled into the 4-inch round frame tube, so you can use the supplied self-tapping bolts to screw the backs of these seat tracks into the frame tube.
Step 3: Install Rear Bolts for Both Seat Tracks
Push the seat track tops all the way to the rear position and drill the front seat-track bolt holes 10-13/16 inches center to center in front of the rear holes. Measure it out and drill, remembering these tracks must be parallel with each other or the seat won’t move. After drilling the holes, you can install the seat tracks as we have done. If you drilled into the black metal floor or frame, you can use a self-tapping bolt. If you went through aluminum, use a stainless-steel bolt, washer, and a locknut.
Step 4: Drill Driver-Side Seat Frame
Here is one of many crucially important steps in properly installing the driver-side seat track and seat. After measuring the distance between all four bolt studs in the seat tracks numerous times, we drilled the seat frame of the driver’s seat to accommodate those mounting bolts. We used the empty Hooker headers’ box as a platform to drill upon, being extremely careful not to drill through any Cobra leather. We refuse to divulge exactly what our measurements were for doing this process because we want you to carefully measure your specific installation yourselves. This hopefully means that you measure many times and only need to drill the holes in the seat frame once. We did not make any miscalculations, though we did clean up our drilled holes with a round hand file, before installing the driver-side seat.
Step 5: Install Driver-Side Seat
After drilling the four holes properly, install the seat on the seat tracks’ four mounting studs and tighten the locknuts. After you have the driver-side seat in place, climb in and test out the travel of your seat. If your seat doesn’t move, you don’t have the two seat tracks installed parallel to each other. If you cannot find a comfortable driving position, start over. Fortunately, we had a good fit.
Step 6: Install Driver-Side Seat
If you’ve installed your driver-side seat correctly, here’s how the install should look with the seat bottom held out of the way. After the adjustable driver’s seat is installed, it’s easy to install the passenger’s side. Simply place the passenger’s seat where you want it to be, drill four holes through the seat frame and the floor below, and install the fasteners. If you go into the frame, you can use the supplied self-tapping bolts. If you go into aluminum only, you’ll need to use stainless-steel bolts, washers, and locknuts. Hint: We decided to have the seats aligned perfectly, so we drew a line on the passenger-side floor exactly as we did for the driver’s side. We then installed the passenger’s seat in that stationary position.
Step 7: Inspect Installed Seats
If you installed modern racing seats in your Cobra replica, perhaps you shouldn’t look at this photo. The driver-side seat is about 1-inch higher off the floor than the passenger’s side, due to being on the adjustable seat tracks, but you can’t see any difference from this vantage point. What you can see is how great the original-style leather seats look in a Cobra replica.
Try as we might, we could not get the FFR-supplied emergency-brake (E-brake) system to work properly, after we fully installed the system. Remember, we’re using a Tremec T56 Magnum 6-speed manual transmission that has never been installed in a Factory Five Racing Mk4 roadster chassis. The case of this transmission is wider and longer than any FFR-supported Tremec transmission.
When we finally installed the supplied E-brake system, the bracket that holds the E-brake on the passenger’s side of the transmission tunnel interfered with the E-brake T-connector cable when setting the E-brake. There simply was no way that we could modify the existing emergency-brake system so that it worked effectively.
Rather than try to re-engineer these E-brake components, we ordered a Lokar universally adjustable chrome E-brake system and emergency brake cables. To our delight, the Lokar system is easy to install and offers great adjustability. If you’re building an FFR Mk4 (and don’t have a Tremec T56 Magnum 6-speed), and you wish to install Factory Five’s emergency brake system, follow the FFR Mk4 Complete Kit manual. If you wish to install Lokar’s system, follow these steps.
Project 6: Emergency-Brake Installation
Step 1: Inspect Components
We ordered the Lokar chrome universal emergency-brake handle and universal emergency brake cables, which were everything we needed to equip our FFR Mk4 Cobra roadster replica with a superior E-brake system. Everything about these components is high quality and the instructions were through and easy to understand.
Step 2: Drill Emergency-Brake Handle Holes
Though Lokar’s universal E-brake handle is designed to install in the floor, we knew we could install the handle on the top of the transmission tunnel. We learned this from doing some investigative work on the two Cobra replica Web forums, www.FFCars.com and www.ClubCobra. com. We confirmed this was an excellent location for the Lokar E-brake handle with Thomas Mauldin, owner of Texas Venom. Thomas is our good friend and fellow FFR replica enthusiast. He’s building his own FFR Mk4 roadster and has created many great FFR Type 65 Coupe replicas and FFR Mk1, Mk2, Mk3, and Mk4 Cobra roadster replicas for customers over the years. We figured out the optimal place to install the Lokar handle and drilled the top of the transmission tunnel frame. Hint: Put some masking tape on the slippery powdercoated frame and then punch drill bit starter holes through the masking tape. Drilling through the Lokar E-brake handle’s mounting bracket holes also helped keep the drill bit where it needs to be.
Step 3: Install Adjustable Emergency-Brake Cables
Following Lokar’s directions, install the adjustable E-brake cables holder, which is held in place with the supplied cotter pin as shown.
Step 4: Install and Route Emergency-Brake Cables
One of the most challenging aspects of installing the E-brake system is carefully routing the passenger- and driver-side E-brake cables to the Lokar cable holder. Keep the cables away from any of the moving suspension components, whether you have an IRS system or a solidaxle Cobra replica. After you successfully route the cables towards the Lokar handle, put the two cables through the FFR frame eyelets as shown in the right of this photo. Then put the cable ends through the Lokar E-brake cables holder holes, being sure to have the cable sheaths removed from the cable ends. The cable ends are held tight with set-screws that are tightened with a hex key. Make certain that these set-screws are nice and tight. Notice that we also used some blue thread locker on the adjustment bolt, so that we can be certain that all is nice and tight. And then install the handle.
If you wish to run the engine in your Cobra chassis before installing the body, you need to install the sidepipes. In fact, the best way to identify any rattles in the chassis is by driving your roadster without the body. You may need to trailer the chassis to a remote parking lot or some other deserted location. Be sure it’s safe to drive around and see how well everything works. Making adjustments to the chassis is much easier without the body installed, but be sure you won’t get into trouble by tooling around in just your Cobra chassis.
If your engine is equipped with electronic fuel injection, start the engine with the sidepipes installed and the oxygen sensor in place in one of the sidepipes. Otherwise, you could damage your electronic fuel injection’s electronic control unit (ECU). You’re also better off installing the sidepipes and fitting the sidepipes’ brackets. Depending on what drivetrain you’re using, you may need to customize your sidepipe hangers, similar to what we’ve done.
Project 7: Sidepipe Installation
Step 1: Install Sidepipes
The first step in installing the stainlesssteel sidepipes is to find the fasteners and the gaskets. Snug the four supplied bolts/nuts tight enough to hold the sidepipes well and find a box or a spare jack stand to prop up the sidepipe.
Step 2: Install Sidepipe Brackets
Factory Five Racing also supplies two first-rate stainless-steel sidepipe brackets, which very safely and securely installs the sidepipes. The button head fasteners, replete with locknuts are also stainless steel. Snug the two button-head bolts with the locknuts against the installation mount on the side of the sidepipes. You install these so you can see where to drill the two other installation holes into the chassis tube that is located at the back of the footbox floor on both the driver’s and passenger’s side. First use a small drill bit to drill a pilot hole. Then drill a hole large enough to accommodate the long bolts that run from the back of the footbox beneath the floor and into the undercarriage. If memory serves, we used a 1/4-inch drill bit; but don’t quote us on that. Match up the diameter of the FFR supplied bolts with the appropriate-size drill bit. Drill the holes from underneath the car. You can make your job easier by using the appropriate-sized uni-bit drill bit from a hardware store. Unfortunately, we weren’t able to find one in the two stores that we visited. So we suffered through with the drill bits that we had in our toolbox.
Step 3: Install Passenger-Side Bracket for Sidepipe
Warner’s Mufflers again came to our rescue by welding a stainless-steel mounting tab to our driver-side sidepipe bracket. To properly install the driver-side bracket, we needed this additional mounting tab. We also needed to modify the passenger-side sidepipe hanger. We drilled through the stainless-steel bracket itself, so we borrowed our next-door neighbor Mike Wilson’s drill press. Drilling through the hard stainless steel is a royal pain. We fried a couple cobalt drill bits before we finally had the additional hole bored. We also purchased a couple extra rubber exhaust hangers, one of which we cut in half for the passenger’s side. We were just fitting these sidepipes temporarily; so when you do, snug the locknuts to about 90-percent of their required tightness. If you’re going to drive your car around as a go-cart to see if there are any rattles that need to be remedied or any adjustments that you need to make, be sure every nut and bolt is nice and tight.
The weather strip needs to be in place so that the body sits correctly on the chassis. This is crucial, because the first and second steps in the bodywork and paint prep process are: proper alignment of the body on the chassis/ frame and getting the doors, hood, and trunk to align perfectly with the body.
There is a FFR decal on the nose of the body. It states that the hood, trunk, and doors are cut a bit oversize and that they need to be trimmed to make a 3/16-inch gap all around the openings. This gap will be perfect, because various painting materials build up to narrow it.
Project 8: Weather Strip Installation
Step 1: Install Weather Strip on Trunk Hoop
If you’re building an FFR Mk4 roadster too, the weather strip and shears are all you need for this part of the build. The rectangular-shaped weather strip (PN-10857) has an adhesive backing. This weather strip frames the engine bay and is also used on top of the frame hoop that arches over the trunk. The other weather strip we installed goes on top of some of the aluminum panels in a friction fit. Stick the rectangular weather strip along the trunk hoop by peeling back the wax paper on the back of the weather strip, and cut off the other end at the end of the frame hoop. Before sticking this little strip on, make sure that all your frame rails and the aluminum panels are clean and free of any dust or dirt.
Step 2: Install Weather Strip on Engine Bay Frame
Now that you know how to install the adhesive-backed weather strip like a pro, put the weather strip on the frame tubes that run the length of the engine bay. For the driver-side tube, stop the weather strip before the top of the pedal box. Install the weather strip on the passenger-side tube as well. We ran ours up to this point. For both sides, they run down to the point where the frame angles down and terminate before the frame angles down.
Step 3: Install Weather Strip atop Firewall
Measure how much friction-fit weather strip needs to be installed on top of the aluminum firewall panel. Cut the length you need and push the weather strip onto the firewall aluminum panel. You may need to pry the weather strip material apart with a flat-blade screwdriver to get the material pliable enough to beginning installing it on the aluminum panel.
Step 4: Pry Weather Strip Apart
To make your friction-fit weather strip that much easier to apply, first pry the groove apart a little bit with a large flat-blade screwdriver.
Step 5: Install Weather Strip on Trunk
Patiently push down on the friction fit weather strip atop the trunk aluminum walls to get a good even fit on this material. Factory Five Racing provides a liberal amount of weather strip in the Mk4 Complete Kit. Even after installing it, you should have some left over. This proves to be a good thing because you likely need to replace some of the weather strip after installing and removing the roadster body two or three times for bodywork and painting.
Step 6: Install Quickjack Bolts and Sleeves
After you and your friends have put the body back on the chassis, install the four Quickjack bolts and sleeves. These four fasteners let you properly locate and align the body on the chassis. One huge word of caution here: Though the picture shows the bolts running from the inside of the body to the outside of the body with the locknuts on the outside, this is incorrect. The FFR Mk4 Complete manual shows this as the way to install the rear bolts. Run the bolts from the outside in. In other words, have the heads of the bolts on the outside and the threads and locknuts on the inside. If you do it in this fashion, you shouldn’t have to drop the fuel tank. When you’ve tightened these four fasteners, you can load your Cobra replica on/in your trailer and head to your designated body and paint experts. Otherwise, you can start fitting the doors to begin the bodywork process.
Written by D. Brian Smith and Posted with Permission of CarTechBooks