Cam Suggestions for 4x4 Ford 429

[Brent W]

Birken asked:

>I am building a Ford 429 for my 4-wheel drive truck. Basically the
>major concern is maximum torque right off idle. Should I buy a
>normal "torque" cam for the first stage of the build, and get a turbo
>grind later?  Also, I have been wondering about the suitability of an
>automatic transmission with this type of power delivery.  My major
>intended use is super slow crawling.  Would I need to change to a
>different cam later if I turbocharge the engine?
> Birken

It would be difficult to beat the factory heavy duty truck application cam
shaft for the Ford 429 engine since they were made specifically to have high
low speed torque and used to pull heavy loads up steep hills. These cams
were generally put into the 429 used with a 2-bbl carb and sometimes even
with a speed governor for the super heavy duty trucks like the dump trucks
and 2-5 ton trucks. The power curve was from 500-3500 rpm. It is a good low
rpm cam which is optimized for low speed torque applications.

Another option would be to use an aftermarket "torque" cam with a split
duration with more duration for the exhaust and less for the intake. For a
large cubic inch engine, you would want to look at a cam with the intake
duration ranging from about 240 to 250 degrees with about 260 degrees
exhaust duration. These cams are optimized for the 800-4000 rpm speed range.

The reason that these types of cams are listed as "torque" cams is because
they are designed for volumetric efficiency. This means that they try to
fill the cylinders as much as possible without intermixing the intake charge
with the exhaust gases and they try to extract the most power (BMEP or Brake
Mean Effective Pressure) out of each combustion cycle. This is done at the
expense of high rpm engine speed. These types of cams make the best cams for
automatic transmissions also. These cams also do very well with
turbochargers, and I wouldn't expect that you would have to change to a
different cam if you decided to install a turbocharger on your engine at a
later time.

This advise only holds true for engines used in low rpm applications like
off-roading where good low speed pulling is the predominant mode of
operation of the engine. Although an on-road application where you desire
good gas mileage and you travel at normal road speeds, then this same type
of torque cam would be just fine also. If the engine is a small block
engine, then you would want to choose a cam with a little less duration than
that used in the big block engines. If you have a racing or on-road high
speed application, one where you are wanting the most horsepower instead of
the most torque, then you would want a different cam with longer duration
and more overlap.

Best of luck to you,
Brent Wiscombe
bwiscombe at msn.com
Mesa, AZ