Got the new motor running but a Q about idle.
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Senior Member
Joined: Dec 1999
Posts: 656
Likes: 0
From: Northglenn, CO, USA
Car: 91' Z28
Engine: 355-Supercharged
Transmission: 700R4
Got the new motor running but a Q about idle.
Ok so she runs pretty good in park, the idle is a little jumpy but really good compared to a week ago, anyway in park it idles at about 1k rpm, but when i put the car into gear it almost wants to die and runs really slugish, so im thinking to myself more throttle right !! well one problem, the idle screw is at it's max (BBK 58mm tb) is it not un-common to remove the old idle screw and replace it with a longer one after a pretty wild cam ?
And secondly when i get the car out on the street it will drive okay after it stumbles out of first, but sometimes it will sort of jerk forward and the engine will drop rpm's dramatically, any idea what that might be attributed to ?
Oh and one more thing i dont seem to have any power brakes, all the hoses appear to be in the right places, i heard sometimes cams dont make enough vac to support power brakes is this true, and if so what can be done about it ?
here's the cams specs and other stuff..
355 .030 over 9.1 compression
AFR 195 heads
Comp Camps roller grind for blower specs:
276 intake
290 exhaust
220 at .050
230 at .050
510 intake with 1.5 rocker
510 exhaust with 1.5 rocker
114 lobe
Crane aluminum rockers 1.6 ratio
And secondly when i get the car out on the street it will drive okay after it stumbles out of first, but sometimes it will sort of jerk forward and the engine will drop rpm's dramatically, any idea what that might be attributed to ?
Oh and one more thing i dont seem to have any power brakes, all the hoses appear to be in the right places, i heard sometimes cams dont make enough vac to support power brakes is this true, and if so what can be done about it ?
here's the cams specs and other stuff..
355 .030 over 9.1 compression
AFR 195 heads
Comp Camps roller grind for blower specs:
276 intake
290 exhaust
220 at .050
230 at .050
510 intake with 1.5 rocker
510 exhaust with 1.5 rocker
114 lobe
Crane aluminum rockers 1.6 ratio
Senior Member
Joined: Oct 1999
Posts: 548
Likes: 0
From: Dallas, Texas
Car: 1991 Z28
Engine: 5.3 Gen III SBC
Transmission: 4L80E NTC 258mm Stall
Axle/Gears: Trick Chassis 9" 3.50 S-Strac
hmm so is it decent driving? that is the exact cam I have and I was wondering about daily drivablity until I can the a programmer. that is the CC305 cam and with 1.6 rockers you have .544 lift. the "jerking" is problably cam surge. with good tuning it will be barely if at all noticeable. and from what I heard on many LT1's (the CC305 cam is a popular cam for them) they dont have any vacuum problems.
Thanks for posting your results. I was wondering what to expect. do you have stock injectors? and are you running lean/ rich anywhere in the RPM band? How is starting. and are you on stock programing?
Thanks for posting your results. I was wondering what to expect. do you have stock injectors? and are you running lean/ rich anywhere in the RPM band? How is starting. and are you on stock programing?
Last edited by Chris Etemadi; Jul 21, 2002 at 01:22 AM.
Thread Starter
Senior Member
Joined: Dec 1999
Posts: 656
Likes: 0
From: Northglenn, CO, USA
Car: 91' Z28
Engine: 355-Supercharged
Transmission: 700R4
Chris, im not on the stock chip, however it still may work with it, i had a guy burn me one with some diffrent values to compensate for my 32# injectors, it starts pretty good, and i dont seem to have and rich conditions from 1k to 3500k rpms, i havent reved it above that yet. Anyway good luck with yours -jeremy-
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