Lunati cam Question

[akart]

I put a Luniti cam in 1000-5000 rpm .454/.468 in my '86 k20. I like it.
What would be the differences if I use the 0-5000 rpm .437/.454 cam in the next build. Mileage/torque/easier in components,HP, What ??
I don't tow anything. ELD 600 cfm & EPS Manifold. Stock engine.

[Ziegelsteinfaust]

Cams are science, black arts, and dumb luck all mixed together.

The 0-5000 cam will have better off throttle take off vs the 1000-5000 cam. Which likely would have better off idle performance.

But a cam is only one portion of a engine build, and everything has to match for optimal performance. As I always tell people there's 350hp then there's 350hp.

You can do it the old school way, and you will have 350hp. Or you can do it right have your 350hp, but with power everywhere else too.

So if your looking for power of some sort I would look to a late model 350 Vortec with the roller cam. A mild build with full bolt ons on that engine works great for heavier trucks

[Nick_R_23]

There's a lot more to a camshaft than just it's RPM range and lift numbers. A wider lobe separation angle typically results in better mileage and a smoother idle. Lobe profile/ramp steepness will determine how hard the cam is on valvetrain conponents. You can have a low lift cam that will eat springs for breakfast and also a high lift cam that will have springs last a long time, all dependent on ramp angles.

To properly determine what camshaft you'll need for your application, you'll typically want the following info:

Vehicle weight
Intended use (towing, drag racing, street car, road racing, marine, etc)
Intended RPM range (be realistic, most vehicles, especially trucks, won't be pushing 6500-7000 RPM)
Engine displacement
Compression ratio
Any flow mods (carb size, intake, head runner flow specs, exhaust size)
Transmission (manual/automatic - torque converter stall)
Final gear ratio
Tire size

You should also let them know what you expect as far as power output, fuel mileage, preferred idle (smooth, rough, lopey), and valvetrain life. Many extreme lobe profiles will give you excellent power numbers, but you may be changing springs at 30K miles.

Providing any major cam manufacturer with this info will get you a good recommendation of the cam you should run. Many times, they will spec you a custom cam, but you can request a proven, off the shelf cam that will be very close and work perfectly in your application.

[MikeB]

Originally Posted by akart

ELD 600 cfm & EPS Manifold. Stock engine.

That pretty much says it all. The Performer EPS manifold is designed to make peak torque at around 3500 RPM in a 350, so any cam you choose needs to have the same objective.

What are the duration numbers on your current cam? I suspect that with the valve lift numbers you posted, going bigger would take a toll on vacuum, torque, and certainly throttle response.

[akart]

Originally Posted by MikeB

That pretty much says it all. The Performer EPS manifold is designed to make peak torque at around 3500 RPM in a 350, so any cam you choose needs to have the same objective.

What are the duration numbers on your current cam? I suspect that with the valve lift numbers you posted, going bigger would take a toll on vacuum, torque, and certainly throttle response.

Duration is 213/ 219 and my question is the effect of a lesser cam .437"/454" Duration 207/213.

[akart]

Originally Posted by Ziegelsteinfaust

Cams are science, black arts, and dumb luck all mixed together.

The 0-5000 cam will have better off throttle take off vs the 1000-5000 cam. Which likely would have better off idle performance.

But a cam is only one portion of a engine build, and everything has to match for optimal performance. As I always tell people there's 350hp then there's 350hp.

You can do it the old school way, and you will have 350hp. Or you can do it right have your 350hp, but with power everywhere else too.

So if your looking for power of some sort I would look to a late model 350 Vortec with the roller cam. A mild build with full bolt ons on that engine works great for heavier trucks

I hate vortec heads. Seems dumb to spend +1000.00 on roller cam,manifold,roller lifters. valve covers and What?,waste my time in junk yards looking @cracked heads and recondition them and the vortec are not that great proformance wise compared to a good set (most any set) of after market heads like AFR or Dart. That is where I would spend my bucks for a HP boost.
I like old school flat hydrolic tappets ZDDP and Valvoline racing oil'
Enjoy your vortec.

[MikeB]

Originally Posted by akart

Duration is 213/ 219 and my question is the effect of a lesser cam .437"/454" Duration 207/213.

Sorry. I misunderstood. Speed reading doesn't always work!

The smaller cam is probably a better match for your other parts. It will make peak torque at a lower RPM, and probably even more torque. It will give up horsepower at higher RPM, I'd guess 4500 and up. The engine should get a little better gas mileage, too.

But, hey, if you like the current cam, keep it.

Vortecs do have their problems, but flow better up to approx .500" lift than any previous cast iron production head. And they really shine at mid-lift where the valve spends half its time. That said, I have a pair on my truck's 350, but would do something different next time.

[Nick_R_23]

Originally Posted by akart

Duration is 213/ 219 and my question is the effect of a lesser cam .437"/454" Duration 207/213.

Do you have links with the full info on both the camshaft you have now and the camshaft you're looking at? There an awful lot of missing info here to properly determine which would be better for your setup.

[Nick_R_23]

Nevermind, managed to find cam cards for them online.

Short answer, the cams are similar enough that I wouldn't spend the time or money to change them out. Ramp profiles are very, very close, so the cams have about the same amount of aggressiveness. LSA and advance are the same for both, so as far as driveability and performance goes, you won't see much of a difference, if any. The smaller cam has better valve timing events (mainly, shorter intake valve opening and closure), which will slightly improve mileage and low end torque.

If you're happy with how your current cam performs, stick with what you have.

[Tom]

No point in the smaller cam. The bigger one starts at 1000rpm....tell me again the last time you used your engine at 1000rpm? Anyways its still a very small cam nothing to worry about just use it.