Originally Posted by TruBlu351
Run thru some different cam profiles on desktop dyno. I know its a very open question, ref the whole RPM range, but just asking in general terms.
Would you prefer an extra 30ft/lbs of torque or 30HP?
The answer is that it depends on what RPM each occurs. Also, if a camshaft "steals" torque from one RPM area to move it to another area, it may be a "bad thing" depending on the RPM ranges involved.
The corrected answer should be that you want to build the broadest, flatest possible torque for the engine and its intended usage. If it is a street engine, you want basically 1800-5500. Don't give up 15-25 foot pounds at 2000 to move them to 4000+ for example. If a camshaft takes a few from the bottom end RPM range and adds a bunch more to the 3600-4200 area in a "hot" street car, that is probably a good thing. As you can see, it is all rather subjective and very dependent on both usage and "when" everything is happening. (when = RPM)
If the car never or very rarely sees the drag strip, focus on making the best possible torque up to about 3800 RPM. This means dual plane intake, small port heads/extractors even a 2bbl carburetor is something very worthwhile considering. Peak RPM on a cam like this would definitely be nosing over by 5000 RPM. A small (500-600) 4bbl or a spreadbore with vacuum secondaries.
If the car is more likely to see some time at the track, a mid-RPM range power band, some more converter and rear gear is going to see a peak torque around 4200-4600 RPM being the sweet spot for a camshaft profile that also makes very broad torque from about 2500-5000 RPM.
A bit "more of everything" will push it out to about a 3800-6500 RPM engine. These are absolutely great for a lightweight stick car that sees limited street duty and plays a good bit of time as a strip thrasher.
A "big cam" where an engine makes power between 4000+ and up to maximum redline is going to be mostly non-streetable and a good bit of a PITA on cruise nights, but will be considered a very "nasty" animal by everyone encountering it. Nearly every single part on an engine like this needs special attention. You can easily build one using mostly stock parts, but by the time someone is looking into this range of activity, aftermarket hot-up parts tend to fill the list of what's going into it.
You may want to take a quick look at the "camshaft selection" section of this:
...PDF file. It really makes good sense to consider these "intended usage" values and carefully note their recommended RPM ranges. Basically, you'll find that a particular camshaft simply moves the RPM range where the engine makes power. A camshaft is really the "brains" of the engine and the cylinder heads are its "heart." As Cleveland owners, we've already got a lot of heart in just the factory pieces. Find a camshaft that puts you as solidly into the RPM range where you intend to use the vehicle. Focus on making the broadest and "overall" highest amount of torque. Don't let the curve slip down in the front end for a bit more peak somewhere else, rather, find one that "comes up quickly" and "stays up a long time." This is a proven strategy for any man!