Cam advice on vortec 350

[1995mudslut]

Hey all i have a 98 that im looking to spruce up some,I have some lifter noise and a bad injector so I want to throw in a new cam while im at it.I've been reading around some and zz4 seems to be the most popular choice for just a mild cam.However, Im wanting a choppy noticeable idle and I've read the zz4 just won't produce that.My truck is not a daily driver so I wouldn't mind something aggressive but at the same time I still want to keep decent gas mileage. I'm trying to do this without any machine work being done if possible.


My truck is lifted on 35's with 4.88 gears so its got low end power but i just want more power all around with a nice lopey idle.

Any suggestions?

[Doober]

Choppy idle + 4.88s + 35s won't give you decent mileage. That's quite a bit of ire/wheel to turn and you need torque. That means higher port velocity at lower rpms, meaning higher vacuum and a smoother idle. A Comp XR264HR would be a good compliment but you won't have your choppy idle.

[Fast305]

Choppy idle + 4.88s + 35s won't give you decent mileage. That's quite a bit of ire/wheel to turn and you need torque. That means higher port velocity at lower rpms, meaning higher vacuum and a smoother idle. A Comp XR264HR would be a good compliment but you won't have your choppy idle.

If he wants lope (and tuning issues) tighten the ever living crap out of the LSA. A 108 or even 106 LSA with a mild duration will be tons of midrange torque with lots of idle lope.

[96ImpSS]

If he wants lope (and tuning issues) tighten the ever living crap out of the LSA. A 108 or even 106 LSA with a mild duration will be tons of midrange torque with lots of idle lope.
/\ What he said /\
The ZZ4 has only a hint of a rough idle and will give up some low end torque to the stock cam. It really comes on about 3000 rpm.
Ask Comp to grind you something like this with XE lobes: 206/212/108 +4. You'll lose less than 1 mpg compared to the stock cam. And you can get that back and more with a good tune.

[1995mudslut]

/\ What he said /\
The ZZ4 has only a hint of a rough idle and will give up some low end torque to the stock cam. It really comes on about 3000 rpm.
Ask Comp to grind you something like this with XE lobes: 206/212/108 +4. You'll lose less than 1 mpg compared to the stock cam. And you can get that back and more with a good tune.

With this grind you mention how much power would i increase?Or does it simply just give it a chopy idle

[96ImpSS]

With this grind you mention how much power would i increase?Or does it simply just give it a chopy idleThat Comp grind I mentioned will definitely pick up some power over the stock cam. I'd estimate 25 hp.

[1995mudslut]

And where would the power range of that cam be?

[96ImpSS]

From idle to 5000 rpm with the stock L31 intake.

[1995mudslut]

ok How much more is a custom grind usually? I noticed you support pcmforless how good can he dail in a cam tune?

[96ImpSS]

Custom grind from Comp was $30 more than their shelf cams 5 years ago when I last ordered one.
pcmforless can definitely do as good as any mail order program out there.
But.....if you're anywhere near a dyno tuner, it would be worth it to bypass the mail order

[BlacK20]

i would like to see someone get a truck with a 107LSA to run right. :lol:

imho, lopey idle, 4.88's, 35's. just dont mix.

[96ImpSS]

i would like to see someone get a truck with a 107LSA to run right. :lol:

imho, lopey idle, 4.88's, 35's. just dont mix.
Your first comment just shows you gather information on the net without understanding the context of it. An LSA number by itself means nothing. I could grind you a cam with 107 LSA with zero overlap.
Your second comment is perfectly vaild, since it's your opinion :) and in many cases, you're right about that ;)

[1995mudslut]

i would like to see someone get a truck with a 107LSA to run right. :lol:

imho, lopey idle, 4.88's, 35's. just dont mix.


How do you figure those dont mix? I know very little about cams but in no way do I see it not mixing.

Lopey idle usually means you lose power right? Well im already 1 gear ratio under geared meaning I could take a little hit on torque and still have plenty of power.

[Doober]

Big lopey cams are a very poor choice for something you drive on a regular basis. You would need to change your torque converter to boot, otherwise it would take its sweet time to get moving compared to a more appropriate cam. "1 ratio undergeared" is putting it mild (shortest stock gear in your garden variety is 4.10, 4.56 is more special order and I'm pretty sure tow trucks, etc. come with it) doesn't make much sense. You can use any gear ratio you want, but it needs to match what you're trying to do with the vehicle. Your 4.88 gear with 35" tires is nearly identical to running a 4.10 with stock size tires. It's ok for a mild cam, but with a big lopey cam it still won't give you much torque down low, and you can only gear so much before it becomes unreasonable. The truck would likely be sluggish and unresponsive around town. Basically it would be like a ricer... lots of noise without lots of results.

Stick with a cam that starts below 1,500 rpm and you'll be happier, especially with an otherwise stock 350. Leave the choppy race car idle to race cars and weekend cruisers. Very slight lope would probably be ok but it's borderline.

This is my Malibu, 350 w/ Vortec heads & carbed intake, it's about the biggest you would want to go, especially with a heavy truck and mediocre gearing. I eased into it in the 2nd clip.
http://www.youtube.com/watch?v=GhN7NHru--Y
http://youtu.be/FwI9H1p574Q

[96ImpSS]

Doober, when performance is the goal, you're absolutely right on all counts.
But when people insist on doing other things, we still try to guide them to protect them from straying too far ;)
It's consistent on just about every enthusiast board you frequent, how many people want to change cams without ever seeing close to the potential of their stock cam.

[1995mudslut]

Big lopey cams are a very poor choice for something you drive on a regular basis. You would need to change your torque converter to boot, otherwise it would take its sweet time to get moving compared to a more appropriate cam. "1 ratio undergeared" is putting it mild (shortest stock gear in your garden variety is 4.10, 4.56 is more special order and I'm pretty sure tow trucks, etc. come with it) doesn't make much sense. You can use any gear ratio you want, but it needs to match what you're trying to do with the vehicle. Your 4.88 gear with 35" tires is nearly identical to running a 4.10 with stock size tires. It's ok for a mild cam, but with a big lopey cam it still won't give you much torque down low, and you can only gear so much before it becomes unreasonable. The truck would likely be sluggish and unresponsive around town. Basically it would be like a ricer... lots of noise without lots of results.

Stick with a cam that starts below 1,500 rpm and you'll be happier, especially with an otherwise stock 350. Leave the choppy race car idle to race cars and weekend cruisers. Very slight lope would probably be ok but it's borderline.

This is my Malibu, 350 w/ Vortec heads & carbed intake, it's about the biggest you would want to go, especially with a heavy truck and mediocre gearing. I eased into it in the 2nd clip.
http://www.youtube.com/watch?v=GhN7NHru--Y
http://youtu.be/FwI9H1p574Q

That makes much more sense than what i have been reading, thanks for clearing it up for me.

And as far as you cam goes that lope is actually plenty i just want it to be noticeable.

[The Fiddle]

http://www.lunatipower.com/Product.aspx?id=2010

Might look into Lunati's stuff. I have that cam in my 383 and have idle set for 750 rpm, only trained ears know it isn't stock. Then again I still have stock exhaust manifolds on it.

[silverado_lover]

DOOD U SHULD PUT A 6.0 IN DAT BISH



/silverado_lover

[SUBURBIAN]

Building the engine for sound isn't perfectly right. Objectively. Building it for purpose then having a sound as a result is a different story. To be able to grunt down low, it is going to have to be very subtle. Short duration, a little split on the lobe durations and as tight of an LSA as you can manage. That will give it some.

[ChevyLs1z]

I have heard over something around .480" lift and you'll have clearance problems

[Doober]

Yes, upwards of that range. I have a cam that's .477/.480 with a set of bone stock Vortecs (all the way down to the springs) and I haven't had any problems.