Project COBRA '33

THE REAR END

    A 1933 Ford 2-door sedan come from the factory with a Closed Rear End.  That means the drive shaft is enclosed and the tube that surrounds it is used to limit torque, or any drive line movement such as spring wrap.  While it was possible to rebuild and reuse the stock Rear End, it would not be very wise.  The stock V8 produced very little torque and even less horse power, around 60-80HP.  The stock Rear End parts would simply not be up to the task of delivering all the power the Supercharged engine would make.  We decided early on that we would not reuse any of the stock drive-line components.  In it's place would be a much stronger and reliable Winters Quick Change Rear End.  A Quick Change Rear End is one that allows the user to quickly and easily change a set of heavy duty gears located in the rear of the Rear End assembly, and thus change the effective rear gear, or output ratio.  Our Winters Quick Change comes with a ring and pinion gear of 4:12 to 1.  This means that for every 4.12 revolutions made by the drive-shaft the rear tires would only rotate one (1) time.  Where the Quick change gears comes into play, is that they are located between the ring and pinion and the input shaft, where the drive shaft would attach, and spin the ring gears.  By placing a set of gears in front of the ring gear, you allow the possibility of changing the ratio between the drive-shaft RPM and the pinion gear RPM, this difference would change the axle RPM by multiplying it faster or slower.

     The Quick Change Gears effectively allows you to alter the the final gear ratio.  This is very handy for cars that see double duty as street cars and race or drag cars.  While it would be advantageous to have a lower Rear Gear on the drag strip for faster get away, it would not work as well for the same Rear Gear to be used on the highway.  Here you would want a lower Rear Gear for economy and to keep the noise level down, lower gears would allow the engine to remain in the lower RPM range, this combined with an effective Overdrive transmission makes for a very quite and economical vehicle.

     The Quick Change Gears come in a very wide assortment, allowing virtually a endless combination.  The chart below shows the different gears that are available for the Winters Quick Change, these gears have 10-splines and are cut for street use, meaning they are much quieter.

     Looking at the chart above, you will see that Gear Set #1, with it's two (2) 20 tooth gears provides no change in gearing.  The input gear is the same as the output gear creating a wash, so these two(2) gears would be used if you wanted to keep the final Rear Gear ratio at 4:12 to 1, or the same as the internal ring and pinion gear.  Moving to Gear Set # 17, with it's 22-tooth gear and it's 19-tooth gear, you will see that the final gear ratio is very different.  Depending on how you install the two gears, you would have an effective ratio of 4.76 of 3.55.  We purchased this same set of gears for Project COBRA '33, this will allow us to run a 4.76 ratio on the drag strip but also allow us to flip them over and run a very realistic 3.55 ratio for the highway.  All you need to do in order to switch the gear sets is remove the back panel and pull the gears off and reinstall new ones, or as in our case remove the gears and re-install them in a different order.  You will loose a small amount of Rear Gear lube, so don't forget to top off the Rear End with fresh new gear oil.

TRlANGULATED 4-LINK

     We went to Heidt's Hot Rod shop (www.heidts.com), for the rear end suspension.  We bought their Triangulated 4-Bar set-up.  It positions the rear end in the chassis, and needs no Pan-Hard Bar, which makes more room for the exhaust and over things.  We also chose to use their Coil Over Shocks, which are used to suspend the car or carry it's weight.

Anti-Roll Bar

Project COBRA'33 will use a Jeg's Anti-Roll Bar which will be located directly over the rear end housing and the Anti-Roll Bars arms will attach to the lower control arms.  This should help provide steady cornering and straight take-offs.

FRONT END 

          We optioned for the Heidts Super Ride IFS Front end.  It came with individual A-arms both upper and lower, and will go a long way in making Project COBRA'33 ride smooth and handle great.  We also upgraded to polished A-arms, Chrome Sway-Bar, Stainless Steel hardware and several other minor options including the Wilwood front disc brakes.  The kit features drop spindles (2") and comes with a very heavy well constructed front cross-member.  We also up-graded the rack and pinion unit to include a power assist unit, the engine came with a power steering pump so why not use it?

HEIDT SUPERRIDE IFS

OPTIONS TO THE IFS