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Engine Buff's help me out

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by MudFrog, Jul 29, 2001.

  1. MudFrog

    MudFrog 1/2 ton status

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    Engine Buff\'s help me out

    I possibly plan on using my tax cut/refund money to get a set of vortec heads. I plan on running these for a while on my stock 350 w/TBI. Then I'd like to upgrade my cam and add a TBI spacer. What cam would perform the best with a basically stock engine with the exception of Voretec heads. And is there any way to tell how much more power would be gained by upgrading these 2 parts? Is there anything in paticular I want to look for in the heads? Maybe from a certain year?

    89 K5 Silverado
    <a target="_blank" href=http://mudfrog.rockcrawler.com>http://mudfrog.rockcrawler.com</a>
     
  2. Butch

    Butch 1/2 ton status

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    Re: Engine Buff\'s help me out

    I tell you I went through 3 cams on peoples recommendations and none of them did what "I" wanted. I then called Muelling (sp) and gave them my trucks weight the size motor, type of pistons intake and carb. What gears I was running and the size tires and where I wanted my power to be made. He sent me a cam that did exactly what I asked for and I could not be happier with it. Save your self a lot of trial and error and call who ever you are going to get the cam from. They Know more about them than all of us combined.

    I thought I was wrong once,
    but I was mistaken
     
  3. newyorkin

    newyorkin 1 ton status

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    Re: Engine Buff\'s help me out

    I just asked a similar question about the heads. Don't forget to upgrade your intake manifold when you get the new heads. If you do a search for "vortec heads", my post should come up "were Vortec heads ever stock" or something like that.
    Don't know about your cam question, but calling a specialist is a good tip!

    Ratch
    <a target="_blank" href=http://k5.8m.com>k5.8m.com</a>
    **K5 - What more is there to life?**
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: Engine Buff\'s help me out

    First of all, forget the TBI spacer. For torque you want the carb/tbi as close to the intake ports as possible. Ever notice how small truck intakes are? You don't need the additional plenum volume.

    If you want to do something significant, get the Edelbrock intake. The stock one sucks. Not to mention it won't fit on your Vortec heads.

    I think that if you don't want to modify your TBI, you're probably looking at a Comp Compucam to keep it running properly. Since you're building a 350, and that's what most cams are rated for, get the smallest one or one step bigger. If in doubt, go smaller, you'll be much happier.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Re: Engine Buff\'s help me out

    I did the same thing Butch did...I called Comp Cams and gave them all the info on my truck, weight gears etc. I was leaning towards a much lumpier cam than they recommended before talking to them. I ended up with the 260 HE cam and it performed exactly as I wanted...
    Just be honest with yourself and the cam companies tech line...and you'll get the best advice. Its in their best interest to hook you up with a cam thats gonna make you happy! [​IMG]

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     
  6. MudFrog

    MudFrog 1/2 ton status

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    Re: Engine Buff\'s help me out

    I'll probably go with the Performer manifold. That is what I had on my old truck at least and I thought it was great. I figured I would probably call and see what type of cams the manufacturers recomend.

    84.. Are you refering to adding bigger injectors or what? I don't have a problem wiht doing any upgrades to the TBI as long as it's not too pricey.

    I want a cam that will give me good torque and more HP.. I'm tired of flooring it and my engine working harder but I'm still not going anywhere any faster. I'll be running 33's with 4.10's so hopefully that will help as well.

    89 K5 Silverado
    <a target="_blank" href=http://mudfrog.rockcrawler.com>http://mudfrog.rockcrawler.com</a>
     
  7. Twiz

    Twiz 1/2 ton status

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    Re: Engine Buff\'s help me out

    There has been alot of info posted here about the vortec heads (some of it by yours truly[​IMG])- it's all pretty much in here somewhere!

    I'd check out Comp Cams extream line of cam shafts- I realy like thier profiles, something in the 260 range should work pretty good. But if it's injected, then a compu-cam might be a better choice. I'd like to think I know what I'm talking about but the best advise would be to call.

    Find a cam you really like, then take it back a step- thats the cam you really need!- Trust me on that one!

    Twiztid
     
  8. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Re: Engine Buff\'s help me out

    GM performance parts has just released an aluminum intake designed to let you use your TBI with the new Vortech heads.
    [​IMG] Part Number is: PN12496821. Supposedly its new for 2001.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     
  9. Nrose07

    Nrose07 1/2 ton status

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    Re: Engine Buff\'s help me out

    Well I'll try to keep this short. I have already done this swap with my blazer, first you have to get a vortec intake. Do not get the vortec Performer if you live in any type of climate that gets below 80degrees. The new GM intake that just came out and the Edelbrock Performer RPM are the only two choices. The reason for this is in 96' when the "Vortec" engines appered not only did the heads change but the fuel injection went to multi-port. This means the vortes heads were designed to used with a "dry" intake system (no fuel in the intake just air). Because of this the intake charge dosen't need to be heated to keep the fuel atomized. SOO the heads don't have a exhaust gas crossover. Now you have to find a way to compensate to keep that fuel atomized, both the GM and Performer RPM intakes have a crossover passage under them to heat the manifold. This goes against the style of the new Edelbrock Air-Gap but you have fuel injection, so you need to heat it to maintain drivability. Now you can plumb either exhaust gas of coolant through your intake. I run coolant, takes alittle longer to warm up but its at a regulated temp. Exhaust gas warms up much faster but hurts overall power because of the temp it reaches leans out you mixture. New GM intake VS. Performer RPM: GM. $400, has EGR valve pad (emissions friendly), TBI intake bolt pattern, unknown if the manifold will except larger 670cfm throttle bores without grinding. Performer RPM, $180, square bore, avalible adapters for TBI-square bore. OK, so enough about intakes, next when it comes to cams it all depends, but what you will want to do is step up to new springs and have the valve guide bosses machined down to allow larger cam lift. The vortec heads will not accept much without doing this first. You will also want to get your prom reburned for this combination. Let me know if you have any more questions, Matt.

    Displacement, cubes, and did you say you drive a riceburner???
     
  10. MudFrog

    MudFrog 1/2 ton status

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    Re: Engine Buff\'s help me out

    Hmm... That was some good reading [​IMG].
    I think I might go ahead and do the cam first. The swap to vortec heads keeps getting more and more expensive.

    89 K5 Silverado
    <a target="_blank" href=http://mudfrog.rockcrawler.com>http://mudfrog.rockcrawler.com</a>
     
  11. lukerz

    lukerz 1/2 ton status

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    Re: Engine Buff\'s help me out

    Don't forget to replace lifters when getting a new cam it is a must.
    Lukers

    83 K10 from 76 K5 & 83 C10
    Th350 Np203 355 CID
    31 X 10.5
    Plan on 2" body lift
     
  12. MudFrog

    MudFrog 1/2 ton status

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    Re: Engine Buff\'s help me out

    I have a set of lifters at my house. However I was wondering. Would it be bennificial to go with a roller cam? With the engine being stock that is. Would it be beneficial when I do the upgrade of the heads?

    89 K5 Silverado
    <a target="_blank" href=http://mudfrog.rockcrawler.com>http://mudfrog.rockcrawler.com</a>
     
  13. CaptCrunch

    CaptCrunch 1/2 ton status

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    Re: Engine Buff\'s help me out

    Comp Cams makes some excellent grinds... you have tons of selection which is nice. I also personally love Crower and Lunati cams. Crane is also another excellent choice that has a ton of different grinds. The main thing to keep in mind w/ the computer is the overlap, but I agree call up whichever manufacturer and they will help you select what you need.

    Roller is a great setup that will free up some power and gas milage, but it can be more expensive then some people want to spend. I think w/ a low torque close to stock cam you should be ok w/ just a change in valve springs... you could probably keep the stock valvesprings depending on the lift of the cam you select.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://www.geocities.com/milnerlives_2000/blazer.htm>http://www.geocities.com/milnerlives_2000/blazer.htm</a>
     
  14. Blazer1970

    Blazer1970 1/2 ton status

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    Re: Engine Buff\'s help me out

    If you want to keep the TBI, the only intake that will bolt up to the heads, and fit the TBI throttle body is the GM Performace Parts intake that is designed for Vortec/TBI applications. The TBI system on these trucks is very sensitive to the cam profile that is used. If you want to swap cams, make sure that you get one that the cam manufacturer recommends for use with the TBI system, or your driveability will go down the drain.

    Tim

    70 Blazer CST 4X4 350 SM465 NP205
    87 Burb 4X4 350
    01 GMC 2500HD 4X4 Duramax/Allison
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Engine Buff\'s help me out

    Roller cams rock. They are also wildly expensive..and besides the grin on your face the extra power they "free up" will make, the cost isn't going to be recouped quickly in MPG I'm sure. They make a nice 204/214 (crane?) grind roller cam, but you are looking at somewhere around $400 just for cam and lifters. Something like that cam is best for low end...all the power is before 3500RPM...most of our big heavy trucks have MPG/power problems in the low end, hence the terrible city MPG.
    These are all my opinions, but when and if I finally get this motor together, I will be able to comment on whether all the added expense was worth it.

    I'm going to be using that cam in my truck, with performer (no way was I going to pay GM's prices) and Vortec heads with roller rockers. I've heard, dependent on the stock heads you ahve now, the gain from Vortecs alone is about 40hp. thats a rough guesstimate I'm sure, and I'd say much lower just to make sure you are surprised with the increase : )


    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</a>
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  16. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    Re: Engine Buff\'s help me out

    Mudfrog, I just put the finishing touches on a new motor(.030 over 350) for a good friend if mine that has a '89 K5. We used the Vortec heads with the new GMPP intake. Don't forget to order the self aligning rockers when you get the heads. We went with a Comp hydraulic cam with 214 and 224 degrees of duration at .050 valve lift and .442 and .465 lift with 112 degree lobe separation. We installed a hypertech chip and increased the fuel pressure a couple of pounds. The truck has headers and dual exhaust. This combination turned out to be perfect. This thing has incredible power from around 2200 rpm all the way to 5000. Good luck with your project. Hope this helps.

    '85 K5 : Run it til it breaks, then fix it and go again!
     
  17. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Engine Buff\'s help me out

    Oh yes, and don't forget, you are limited to .450 (ok, maybe its more like .500, but they won't admit it) lift with teh stock vortec head springs.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</a>
    No anti-theft measures on your truck? No pity when its stolen
     
  18. MudFrog

    MudFrog 1/2 ton status

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    Re: Engine Buff\'s help me out

    Mr.Chevy... how much did all this run? I'm assuming you had a shop bore it over.. What I want to do is get the most out of my engine as I can for about 300-400 dollars.. I know thats not a lot but there has to be something I can do in that price range that will make a good difference in power.

    89 K5 Silverado
    <a target="_blank" href=http://mudfrog.rockcrawler.com>http://mudfrog.rockcrawler.com</a>
     
  19. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: Engine Buff\'s help me out

    No, I wasn't referring to getting bigger injectors, I was trying to tell you that you need the Edelbrock Vortec TBI intake.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  20. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: Engine Buff\'s help me out

    No, I wasn't referring to getting bigger injectors, I was trying to tell you that you need the Edelbrock Vortec TBI intake, or something else made for Vortec heads and TBI.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     

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