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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
superweather strip adheisive applied to the ceramic on the plug and then
put on the plug wire while the adheisive 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 dont 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 dont 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 tranmissions myself.
Make sure your transmission dont 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 driveshaft is
gone. If you look at the end of the speedo cable and its turning in gear
then you have no driveshaft 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 dont 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 theend of each coonection, this will help keep the linkage from bieng
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 grommett. 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 Summitt 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
dimintions with another manufacturer if you know what size the belt is.
Fan Blades: I highly reccomend 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 stearing gear box
and stearing column. Many times the front of the car will bow up after a
time and break the gearbox stearingbox 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 arent 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 woth 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 transmissin 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 carburator 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
driveshafts. Most GM passenger cars have what is known as the constant
velocity joint type driveshaft. 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 driveshaft will more flexability and at times I've
even had them dragging the ground but still running without breaking and
putting me out. Without this modification your driveshaft has a much
higher chance of breaking and causing you to finish out of the top. If you
dont understand how this is done surf over to the IDDA gold area for a
pictorial on what this looks like as its being done and the finished
product. If the driveshaft 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
reccomend 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
reccomend 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 reccomend 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 reccomend 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 dont 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
dont 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 heres several suggestions. Aways run tubes in your tires
with the shortest valve stems available. You mak 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 reccomend doing this on the back side of the rim that way you
dont 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.
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