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- - Cam Choice (https://67-72chevytrucks.com/vboard/showthread.php?t=187309)

Ok, I'd like some opinions on this. Which cam would you choose based on the specs? I'll be running a 350 bored .060 over with an RPM intake, 76CC stock heads w/ stock rockers; mostly a daily driver but I'd like to be able to smoke 'em from time to time.

Basic Operating RPM Range: 1,500-5,200 RPM
Intake Duration at 050 inch Lift: 218
Exhaust Duration at 050 inch Lift: 218
Duration at 050 inch Lift: 218 int./218 exh.
Advertised Intake Duration: 284
Advertised Exhaust Duration: 284
Advertised Duration: 284 int./284 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.458
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.458
Valve Lift with Factory Rocker Arm Ratio: 0.458 int./0.458 exh. lift
Lobe Separation (degrees): 110

OR

Basic Operating RPM Range: 1,000-5,500 RPM
Intake Duration at 050 inch Lift: 207
Exhaust Duration at 050 inch Lift: 213
Duration at 050 inch Lift: 207 int./213 exh.
Advertised Intake Duration: 250
Advertised Exhaust Duration: 256
Advertised Duration: 250 int./256 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.437
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.454
Valve Lift with Factory Rocker Arm Ratio: 0.437 int./0.454 exh. lift
Lobe Separation (degrees):

It's a 3 speed manual. I'm not exactly sure about the gears but they've got to be a higher ratio.

Forgot to ask, whos the maker of each cam? I'd lean towards the 2nd one for now for a daily driver. Also the split pattern on the second one will help scavange the cylinder more.

Wow, really shows the worthlessness of "advertised" duration figures! :lol: Those cams aren't too far apart in specs, yet the advertised duration numbers are 284/284 and 250/256! Sorry, got a kick outta that.

I'm not going to try to point you in one direction or another based on this data, but I sure would plug the specs into a dyno program to see what the effects are. I think that'll really help you make a decision.

Thanks for the info 71Chevy and MrC. I purposely didn't provide the maker in my first post but they are both Lunati. The first one is an older cam from them and the second one is one of their new Voodoo cams. I'm leaning towards the second one.

Good point, about not letting us know, I'd lean towards the second one, first its part of the vodoo series and its new, as time goes on cam technology just gets better and better.

Yeah, I just wanted people to look at the specs and not the name.

I'm gonna give the Voodoo a shot but hold on to the older Lunati just in case and I'll let ya'll know how it goes.

Quote:

Originally Posted by Ole Blue 68

You will want to go with the second wone for sure. I have to totally disagee with Mr. C-1 on this. Advertised duration is not worthless by any means. Its an indicator of the intake closing angle and is critical in choosing a cam to match compression ratio. When you look at advertised duration most likely you will see that solid cams are rated @ .020 duration and hydraulics are rated @ .006. This is also somthing that needs to be taken into concideration. The second cam will have much more throttle response, have much more torque, it will probably produce more HP too. Also with your low compression the first cam is way too long on duration and would be a slug down low. 284 advertised duration is somthing i would run with 10:1 compression. Just for reference i run a solid 296/301 advertised 258/264@.050 in my street Nova. Im calculated at a precice 11.1:1 compression and i can still run 89 octane gas anywhere i want. Thats what advertised duration does for you. Its an indicator. 11.1:1 compression and 89 octane gas.....

Thanks for the good info Nova. I'm going with the second one.

Good call, i hope you like it!