GraveReaper0 wrote:
........ So now I want to know how to pick one ........
Although it is probably less complicated than brain surgery, an engineering degree would get you started.
First, you need to be reminded that the cam is only part of the total package.
In order to choose a cam, you will need to know the bore, stroke, head/manifold flow and the planned static and dynamic compression ratios. Among the many other factors, the weight of the car, the trans, rear gears, tires, and how the car will be used.
Once these are known, you will know where to go next. IE: If the trans used will be automatic, a 350, 400, or Glide, each might require a different torque converter, gears, tires, and (you guessed it) cam timing.
Then you'll need to know how any small change in those specs will require changes in the cam profile.
Most of the people you will encounter on the street, or at shows, will use whatever someone else thought would work.
GraveReaper0 wrote:
........ like 204/214 or 220/231 ........
If those numbers are in degrees, they show the amount of time the valves are open. 204=intake, 214=exhaust. Since they are different values, it is called a "split duration" cam. Some think it is better than a single pattern cam, some do not.
If they are in inches, they show the maximum cam or valve lift.
I'm guessing, your examples are generic Olds V8 cams. If so, they show the timing (in degrees) at .050" valve lift.
204°/214°@.050" might be a good choice for a stock 350 because of its impressive idle. Likewise the 220°/231°@.050" for a stock 455.
Here is the cam card for my 437.
As you've seen
here, it works well in my present 437. It may, or may not, work as well with the new heads. Its 39° equivalent did not work as well in my 461.
GraveReaper0 wrote:
........ And what would the difference be in the engine with the above examples?
In theory, the 220°/231° is bigger, so it would make more power. In actual practice, it could make less than it did before someone forked with it.
It is far easier to ask someone else what he/she uses.
Norm
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