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cam for 350vortec

Discussion in 'The Garage' started by 79wheeler, Jun 25, 2005.

  1. 79wheeler

    79wheeler Registered Member

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    Hi, well I am in need of some advice. I have a crate 350 with a gm manifold,headers and some vtec heads. I was wondering what size cam should be used? Any and all advise would be great! :D
     
  2. LongIslander26

    LongIslander26 1/2 ton status

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    Cam choice

    Well, it depends on a lot of things. What type of driving is the vehicle going to see the most of? Highway or around town? Is it a roller cam motor, or flat tappets? What kind of tranny do you have? What rearend gears are in it?
    Are you looking for rockcrawling grunt, or blasting though a mudhole? You need to be honest with yourself too. If you want it to be the ultimate Hi-Po off road machine, but you only go off road say, once every other month, and have to drive it to work everyday, you're probably going to hate driving to work. What RPM range does the engine see the most?
     
  3. 79wheeler

    79wheeler Registered Member

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    hi, well it's my toy, but it will see the highway and pulling my bass boat. It's not going to be an every day driver but some thing for the weeked. It has a 4 speed ,33 on with a 4' lift ,gears not sure on yet. have not had it for long.. not a crawler but all around wheeler... THX.... :D
     
  4. LongIslander26

    LongIslander26 1/2 ton status

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    Cam choice

    With the Vortec heads you are limited to about 0.450" of lift, unless you have the spring seats machined. Assuming the engine is a roller cam, I would look into a cam that gives you the most lift you can get, without going over about 215 degrees of duration at 0.050. Any higher than that and your getting into a "Midrange" cam that you really don't need with an overdrive tranny. You want alot of bottom end torque to get you going quickly off the line with those big tires, and towing your boat. With an overdrive tranny the engine is rarely going to to see the high side of 3500 rpm's, and cruise at around 2 grand. I don't know what the emissions laws are where you live, but you want headers and a free flowing exhaust. Dual setups work well on these trucks with a 2 1/2 in pipe. The compression ratio in that motor is about 9.1/1 stock. That's plenty for a low duration cam to still run on pump gas. The GM intakes are pretty good, and there's really no need to change it. Th GM Vortec intake manifold gaskets are pretty flimsy, and fail pretty quickly. Use a good aftermarket brand like Fel-Pro or Rol. If you like, E-mail me through this site, and I can send you some Dyno-sim charts with a few recommended cams in them, and you can see where the power will be. Or you can call the helpline of the cam manufacturer you want to deal with, and have them recommend something. I'm partial to Comp Cams myself, but I've gotten good results with other manufacturers depending on the application.
     
  5. 79wheeler

    79wheeler Registered Member

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    The motor is just a goodwrench short block flattap, then ordered the vtec heads and intake.. the 4 speed manual is an over drive??? :) hp charts would be great !!! It is a 4 barell carb too.. Thanks alot.... :D
     
  6. Mad-Dog

    Mad-Dog 1/2 ton status

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    I'm going to add my 2 cents and and recommend the Comp HE260H which is a single-pattern hydraulic grind designed for 4wd and towing with a 350cid engine,it has a good idle, strong midrange and specs out at 212/212-260/260-.440/.440" and 110 lsa.
    I believe this would pull the boat nicely and give him a kick in the pants on the back roads....it is also compatible with stock valve springs.
     
  7. LongIslander26

    LongIslander26 1/2 ton status

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    Ahhh, a MANUAL Tranny!

    Ok, so the tranny is a manual. That changes things, since I'm assuming you have a 1:1 final drive ratio out of the tranny, you may want to venture into the low- midrange cams. Is it possible for me to e-mail on this site, or do you have a yahoo messenger name? Mine is the same as my username here. In any event, you're not going to want a cam much higher than 220 degrees @ .050. What year did you say this was?
     
  8. 79wheeler

    79wheeler Registered Member

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    Sorry, I didn't clarify hehehe ... it's a 79 special edition blazer my e-mail is PorkyDanny@aol.com anything would be great...thanks for the help :D :D
     
  9. LongIslander26

    LongIslander26 1/2 ton status

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    Cam choice

    I agree with mad-dog. I was going to recommend the HR 260 if he had a roller cam and the heads would take the lift. I'll print up a dyno sheet and e-mail it to you. My e-mail will be on the e-mail I send you. Cool beans
     
  10. LongIslander26

    LongIslander26 1/2 ton status

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    you have mail

    Check your mailbox, Bro.
     
  11. LongIslander26

    LongIslander26 1/2 ton status

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    Well??

    Did it go through? Did you get it? :confused:
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    Any cam you decide to go with, call them and make SURE that the Vortec springs make enough seat pressure to work with the cam.

    Roller cams are different, but the stock Vortec (which was roller) cam is VERY mild, so even a fairly aggressive hydraulic cam I'd suspect might have spring pressure problems.

    Just some speculation, but along with the lift issue, this is something I had to work around.
     
  13. moturbopar

    moturbopar 1/2 ton status

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    Hi, I have a vortec 350 HO 330hp in my blazer. The cam that comes with this motor is great it a mild hydrolic the specs are at .050 is 212in 222ext .435 lift in and .460 ext on a 112.5. Car craft had an article on this motor. With this cam performer rpm holley 750 and 1 5/8" headers the engine made 371hp and 408ftlb it! My truck idles with 17.5 in of vacuum and has smooth idle and has pleanty of power even though i have the fastory exhaust manifold on it for now.
    Where in AZ are you located?
    Thanks Shawn
     
  14. 79wheeler

    79wheeler Registered Member

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    Hey all, Had some stuff to do... I live in the north valley.you buy that 350motor crate sounds sweet!!! What Kind of low end power do u have? :D .Islander , the mail was just all numbers mabey you could try it agin Thx etheir way...
     
  15. 79wheeler

    79wheeler Registered Member

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    any one know what special edition means????
     
  16. LongIslander26

    LongIslander26 1/2 ton status

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    Crate motor

    I have the same motor with the same cam in my 79 Jimmy. It ran like a raped ape when I lived in Mesa, but up here at 6500 feet of altitude it's lacking a bit of power. I'm actually considering stroking it to 383, and putting a slightly smaller cam in it. (The roller version of the one I recommended to you). Being carbureted is hurting it too I think. I'll try something else to get you that sheet. Hang loose for a minute. "Special edition" was probably just a dealer installed option package that Chevy gave its blessing to.
     
  17. LongIslander26

    LongIslander26 1/2 ton status

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    Dyno sheet

    Well, I could fax it to you, if that's possible, or I could just give you the highlights.

    300hp @ 4500 rpm
    387 lb/ft @ 3500 rpm
    380+ lb/ft from 2000 - 3500 rpm.

    Nice flat torque curve from idle to almost 4 grand.
    Whatever cam you go with, get the springs that are meant for the cam.
     
  18. beater_k20

    beater_k20 Banned

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    pics? Honda heads will not physically bolt to a GM SBC block, im curious to see how you did it.

    V-O-R-T-E-C :screwy:
     
  19. 79wheeler

    79wheeler Registered Member

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    long thanks for the help...ill get a comp cam on monday and finally assemble my motor. do u have pics of your truck? :D beater u know what i meant dont be a dumbass :p:
     
  20. LongIslander26

    LongIslander26 1/2 ton status

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    Truck pics.

    I'll snap a few and post them here. It ain't nothing special paint wise, but it's a good solid AZ truck. It was in alot better shape when I bought from the old lady who was the original owner in Tempe, I've taken it out and womped the crap out of it a time or 2 (Blew the tranny up once as well). I'll get them snapped off and posted here in a day or 2.
     

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