question

a 350 chevy small block out of a 74 blazer four bolt main putting out approx. 8to1 compression . is a comp cams 268 extreme energy to big for the compression? ill tell you why i ask . ive been farting around with this thing and i cant get a flutter type miss out of it at 18 to 22 rpm --cruising rpm other than that it runs smooth. untill you give it a little gas to go up hill or somethin, you get the vibration.i put new cap rotor wires and plus ,rebuilt the carb ,reset the timing 14btdc 34 total,readjusted the valves, retightened every bolt on the motor, it has a performer rpm intake quadrajet carb comp cams stamped steel roller rockers , i just cant find it ! i tried another carb too. no change . any ideas ?

1. "flutter-type miss"

2. "vibration"

They're not the same thing. Do you perhaps have two problems going on.

a flutter type miss that causes a slight vibration between 18 and 2200 is that came to big would that cause this .......also stock converter

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Originally posted by S19243H
a flutter type miss that causes a slight vibration between 18 and 2200 is that came to big would that cause this .......also stock converter

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S19243H, if i had a motor with a "flutter type miss that causes a slight vibration between 18 and 2200" id run like hell. i dont believe a cam could do all that by itself. you need to get us a little better description of what your motor is doing than that. :confused:

good one lts10 even i laughed at that one! let me see if i can explain better. put youre hand on the cab at idle. you can feel a mis throttle up past idle shes smooth until 18 to 2000 rpms then you feel a slight vibration go past 2000 an it goes away hows that!

Quote:

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Originally posted by S19243H
good one lts10 even i laughed at that one! let me see if i can explain better. put youre hand on the cab at idle. you can feel a mis throttle up past idle shes smooth until 18 to 2000 rpms then you feel a slight vibration go past 2000 an it goes away hows that!

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im glade you took it the way it was meant. its really hard to say, but i doubt the cam is doing either. if i had changed all that on the motor, with no change id believe id be checking maybe the drive shaft for the vibration. what does it do 1800-2200 rpm's sitting still?

Hmmm, I am by no means an expert, but, it sounds like, from the onset of timing, and vaccum. That type of shudder seems to me, like something is behind.
You rebuilt the quad, did you try a non-vaccum type of carb? Your timing should be all in at that rpm. It sounds almost like it is leaning out at that point.
What is its performance up to, and over that point? Any other symptoms?

Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.477 0.48
Duration At 0.006 Tappet Lift 268 280

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Valve Timing At 0.006
Open Close
Intake 28 60
Exhaust 74 26

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These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 224 230
Lobe Lift 0.318 0.32
Lobe Separation 110

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These are the specs from Comp for the 268 Extreme energy cam.

I'm no expert on cams but could you be mistaking a "rumpy idle" as a miss? The vibration after rpm increase is concerning, balance issues????:confused:

First of all i want to thank everyone who is trying to help me, DECONE31,i didnt try a non vac carb . it sounds like a lean spot to me too. nly way to tell is dyno for that. from a dead punch shell smoke em till you let off no hessitation or pops lt1s10,at 18 to 2200 sitting still it still has the vibratin s10streeter, im thinking ballance issues to what should i look for

if its doing the samething at 1800 rpm's sitting still or driving, then it would be a vebration issue. flexplate, HB. cooling fan.

I TOOK THE CAR TO WORK TODAY. seems like a sluggish light vibration ,i can feel it in the steering wheel gas peddle and see it in the mirror. and why the hell does it idle so high? to keep it at 750 in gear its 1500 in park. im going to take the belts off and start it and see what happens wish me luck

i think you got 2 problems, a idling problem vac. leak, or rich and a viberation.

i pulled all eight plugs there a little darker than gray not by much i removed the belts ..... no change....whats the best way to find a vac leak ? im showing 12 inches at 1000 rpms

thats a good reason not to idle. unplug all of the external vac. hoses and cap them off. then spray carb. cleaner around the intake and carb. gaskets. what is the vac. gauge hand doing ? dont spray it on the dist.

thanks lt1st, i will keep you posted ill try what you said tomarrow nite after work . so what was the giveaway? BY THE WAY I VISITED YOURE WEB SITE nice truck ! i like the cars too! are those youres blower motors and all?