440 cams and efi

[Bill Edgeworth]

Maxt at nucleus.com wrote:

>  Hughes engines makes chrysler specific cams for the 440 which take
> advantage of the 440's larger lifter area. The larger lifter allows you to
> install a cam
> with larger lift, less duration and overlap, retaining vacuum and idle
> quality .

My understanding of this is that the Mopar large diameter lifters (.904")
allow for a faster rate of opening. Therefore the valve can obtain maximum
lift sooner and for longer than with a small diameter lifter. If you take a
look at a cam timing diagram for a Mopar you can achieve a larger area under
the curve at 050 lift as opposed to some other engines. It is because of
this that you can achieve the same net airflow with a cam of lower duration
and overlap as opposed to a cam using a lobe profile developed for a smaller
diameter lifter using more duration.
In my opinion the Mopar 906 and 452 heads don't really need tons of lift to
achieve maximum flow, unless they have lots of work done to them and have
big valves.
The Hughes cams are an excellent choice for Mopars, depending on the
performance level of the engine Comp Cams manufactures a roller cam with
.550 lift that idles like a Hemi grind.

Bill Edgeworth