It is very important that you run H.E.I. ignition.  The timing must be set to the manufacturers specifications.  A new cap, rotor, and wires are a must.  After replacing the cap and wires use a tie strap one on each side of the cap as an extra measure to hold the cap in place during those hard crunching blows.  The tie straps are sometimes called plastic zip ties. Use the tie straps to route plug wires away from heat sources such as headers, using extra small tie straps wrap these around the spark plug wire boots and pull tight to secure the plug wire to the plug. You can also use 3M super weather strip adhesive applied to the ceramic on the plug and then put on the plug wire while the adhesive is sticky. This method will basically glue the plug wire boot to the plug, it also helps keep the plug from water foul outs.

 

Headers require gaskets.  Many guys don't run gaskets on their cars, only to have their plug wires burn up before the derby is over. These also save your engine during peak temperatures from burning up the valves.

 

Changing the oil and oil filter is also very important.  An engine with fresh oil and filter will run much cooler than one with sludged up oil  and plugged filters. Additives such as Slick 50 or Prolong etc. are also great ways to keep engine temps in control.

 

On engines with high mileages you must be absolutely sure the timing chain is good or replace it with a new one. Broken timing chains waste good cars when they don't finish after running long enough to half destroy a car.

 

If you are running a 350 turbo transmission use a 400 turbo torque converter.  The 400 converter allows you more fluid capacity than the 350, and more fluid means longer recycle times, thus cooler transmission. I prefer the 375 or 400 transmissions myself.

 

Make sure your transmission don't leak anywhere if it leaks fix it. Fluid leaks will kill your chances of winning a derby.  I advise leaving the speedometer cable hooked up.  If you take out all the dash components then route the cable to the top of the steering column and tie strap it secure.  This will help you as driver because if you are in a situation where you are not moving, the cable will tell you things like if your drive shaft is gone.  If you look at the end of the Speedo cable and its turning in gear then you have no drive shaft or have lost the rear end.  If it is not turning try another gear, if it turns and the car moves then you have lost the other gear in the transmission.  If you go through the gears and have no movement you have transmission failure, leaked out too much fluid, toasted the trans, etc. Normally if you lose a gear don't panic and shut down, you may have to sit a second or two to let the fluid settle to the pan and change gears to regain movement, usually you wont lose all gears at the same time, if you do then you are out of fluid more than likely. Check the Speedo cable!

 

Transmission linkage:  If you elect to run the stock linkage weld a washer on the end of each connection, this will help keep the linkage from being pulled apart.  use 1 at the side of the trans, 1 at the frame outside the spring and plastic guide, 3 if the linkage works properly tack weld the adjustment slide, 4 at the column where the adjustment rod goes through the rubber grommet. However the early Chevy Vega automatic shifters are about the best and easiest to convert to the bigger cars, the only modification is lengthening the shifter rod.

 

Radiator & cooling system:  Always use a clean 4 row radiator make sure it is clean and does not leak.  I usually buy a new one each season, its kind of expensive but it does help keep the engine cooler. A good 50/50 mix of water and antifreeze will help but I prefer water and an additive called 40 below,  this additive can be purchased in some auto supply stores or from Jegs or Summit magazine. There are others out there like liquid glass also that work well. Thermostats should be removed due to them failing at the worst times. Replace it with a large washer with a hole in it the size of a dime.  This will allow the water to flow through restricted enough to allow it time to cool in the radiator.  Never run a wide open system it will overheat quickly. If you choose to run your water pump without an alternator you can buy a belt that will go from water pump pulley to the harmonic balancer pulley making it a direct 1to1 ratio.  The belt I have used for years is a Kelly Springfield belt purchased through Auto Zone, Part number 15360.  The belt size is 15/32 in. x 36 in. @ 38 degrees. Most reputable parts stores will be able to match up the size dimensions with another manufacturer if you know what size the belt is.

 

Fan Blades:  I highly recommend a plastic aftermarket fan blade, 6 blades most speed shops will have this blade in stock.  There are 3 advantages to using the plastic blade, (1) is they are light weight. (2) is plastic wont harm the radiator like a metal blade will.  (3) If you position the blade about 1 1/2 inches from the radiator you will draw more air through the radiator than any stock blade can, more air = less temperature.

 

Gear box and column:  Another topic for discussion is the steering gear box and steering column.  Many times the front of the car will bow up after a time and break the gearbox steering box doughnut eliminating your ability to steer the car.  In order to fix this problem go inside the car where the bottom of the column is bolted to the dash undercarriage. Take the 2 nuts off and let the column drop, knock out the studs and replace them with carriage bolts long enough to drop the column 2 to 3 inches.  You'll need spacers to take up the extra space between the column and the dash, use a good size flat washer between the nut and the column to keep it from slipping. This will change the angle of the column so the doughnut is straight in line with the column and the gear box, allowing room for the front end to bow up and the column will be able to return to the angle that was stock.  This will help keep it from binding up and making it very hard to steer.

 

Since we discussed bowing up the front end lets address distributor clearance now.  As the front end bows up the distributor closes the gap between itself and the firewall and will bust the cap at some point if measures aren't taken to remedy the problem.  Here I have 2 suggestions. The first is to cut a hole in the firewall large enough to allow the distributor to pass through it without being damaged. The second would be to fabricate a distributor shield, find a piece of 6 inch pipe and cut it in two length ways 1/4 inch thick is what I use. You should have a piece that looks like a C this will form out to shield the back of the distributor from the firewall.  Some braces will be needed so find some 1/2 inch flat material by 3 inches wide to make braces out of. This will take some ingenuity to fabricate but well worth the trouble. Weld a bracket to each side of the bottom of the pipe to make braces that will go to the transmission bell housing bolts.  Bolt these to the transmission bell bolts the make 2 braces to run from the top of the pipe to the front 2 intake bolts.  You'll need to find some longer bolts for these braces. Your top braces will also serve as protection for your carburetor also, and a place to tie strap down the plug wires between the headers. Once you have this made you'll see that this is the best device to come along in a long time.

 

Now that we've covered the engine and transmission lets talk about drive shafts. Most GM passenger cars have what is known as the constant velocity joint type drive shaft.  In order to prepare the shaft look at the double universal joint at the end of the shaft closest to the rear end differential.  Notice each side has a little tab sticking out.  Take a 4 inch grinder and grind off the tabs.  In other words each u-joint cap area needs ground smooth to match the exact shape of the u-joint caps.  This will allow the rear end housing to turn downward if the frame bends too much in the rear, the drive shaft will more flexibility and at times I've even had them dragging the ground but still running without breaking and putting me out. Without this modification your drive shaft has a much higher chance of breaking and causing you to finish out of the top.  If the drive shaft can touch anywhere at the constant velocity joint it will break when put in that angle.

 

Rear Differential:  Now lets weld the rear end gears for econo posi traction.  Never weld directly to the axle, your axles are heat forged  and welding on them will weaken the strength of the axle.  Also if you welded the axles in you cant change them in case you break one during the heat. I recommend you always have an extra axle on hand just in case you do break one.  Now lets weld those gears.  Only weld the 4 spider gears together, weld where each one touches the one beside it, be careful not to get weld on the c-clips or the slide bar that holds the spider gears in.  If you get weld on these parts you wont be able to change a broken axle either.  I recommend using a Mig welder for this.  The Mig wire is a little more forgiving than the arc welding rods and not as hard.  The only rear end I ever lost in 18 years was welded with an arc welder. It exploded the housing and the gears and put me out for the day.

 

Bumpers:  I highly recommend using a 74 through 76 Chevy Impala or Caprice front bumper, they are the toughest bumpers I know of.  Rear bumpers are optional, but the same years back bumpers are an improvement on most GM models.  I recommend you drill a hole in each bumper shock and collapse it forcing out the oil, once the oil is out weld the shock to the inner shock tube so they are solid.

 

Windshields:  If you don't have to leave in your windshield TAKE IT OUT.  Put expanded metal over at least half of the drivers viewing area, with a bar from the roof to the firewall to keep out debris. Expanded metal is the stuff that looks like a course screen type material that will allow you to see through but protect you at the same time. Windshield break and you don't want to be sitting in glass I guarantee it! Not to mention they are awful hard to se out of once they get mud all over them.

 

Tires:  This is area of much debate.  I personally run 12 ply tow motor tires on my cars when allowed.  Some derbies do have limitations, so taking that into account here's several suggestions.  Always run tubes in your tires with the shortest valve stems available.  You make also weld rocker arms over the valve stem hole to protect them from being torn off.  If you are limited as to the ply rating on the tires, maybe you can screw the tire to the rim, I recommend doing this on the back side of the rim that way you don't tip off the other drivers to your secret to keep the tire on the rim.  Often tires will go flat and spin right off the rim making it near impossible to move, this will help keep the tire on the rim.  A flat tire is still better than no tire.  You might consider running a tire inside a tire also.