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Better RPMs?

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  #1  
Old 07-09-2009, 02:56 PM
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Default Better RPMs?

Well Its not a Camaro buts its got a 350 V8 . 94 Chevy Silverado

I'm going to rebuild the engine but I would love for redline not to be a just 4K What do I have to do to up the RPMs to about 6 redline.
 
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Old 07-09-2009, 04:23 PM
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Hotter cam, matching valve springs, computer tuning, and changing transmission shift points. The Silverado is a pretty heavy vehicle and it needs a lot of low end torque to get rolling. Unless you change final drive ratio to a substantially lower one, the modified engine you are planning is going to labor hard to get the truck rolling.
 
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Old 07-09-2009, 07:55 PM
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Eh... I was actually hoping to make it get a little better MPG... not drink more gas. Crap this backfired in my face. I mean 12 MPG sucks hard when filling it with basic unleaded costs about $70
 
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Old 07-21-2009, 01:29 PM
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A hotter cam will not eat up mpg. Cam only controls how long the valves are open and how far they open. Fuel injectors/carb control fuel flow so going up in injector strength/cfm will effect that. You could also go with an intake with a bit more plenum volume but that will effect your low end.

If you're just looking for more of a top end speed I would look at your transmission, rear gearing and suspension.
 
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Old 07-21-2009, 02:34 PM
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Your 350 is capable of going quite a bit over 4k rpm as it is now, but not nearly as high as 6k. It sounds like the trans is just shifting sooner than you want it to. And you want to get it to 6k? Are you racing the truck? If you use the truck for hauling (more than just azz) then you would want to build the engine more for torque, and not be as concerned with how high it will wind.
 
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Old 07-21-2009, 05:06 PM
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Also, if you have a th350 or th400 they should have an adjustable modulator valve on the side. All you have to do is disconnect the vacuum hose and take a precision screwdriver to it and wind it out (IIRC) to raise the shift points. This will help you with the higher RPM's. Then just reconnect the hose and test drive it. Repeat the process until you get it where you want.
 
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Old 07-21-2009, 06:03 PM
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Originally Posted by kyphur
A hotter cam will not eat up mpg. Cam only controls how long the valves are open and how far they open. Fuel injectors/carb control fuel flow so going up in injector strength/cfm will effect that. You could also go with an intake with a bit more plenum volume but that will effect your low end.

If you're just looking for more of a top end speed I would look at your transmission, rear gearing and suspension.
my cam install dropped me from over 25mpg to somewhere in the mid teens

at normal driving conditions the overlap is such that you blow alot of unburnt fuel out the exhaust and have to compensate to make normal power by adding extra fuel. even the idle is pig rich now
 
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Old 07-21-2009, 06:22 PM
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Not to change the subject, but Spec I've been meaning to ask you this since you announced your car is up for sale.....How does your car pass emissions, or don't you have to test where you're at?
 
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Old 07-21-2009, 06:46 PM
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ill pm u
 
  #10  
Old 07-21-2009, 07:08 PM
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Blue should have the 4L60E, unless it's been swapped out. Shift points are controlled by the PCM. He would need a computer tune to change up-shift points while in "automatic" mode.
 


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