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What cam to buy.....

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 84CUCV, Jun 26, 2004.

  1. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    Well, the cam on my sub flatned out. So I was going to by a cam with lifters from PAW. Then I thought I might as well see about a little more HP at the same time. I was thinking about a 4x4 cam. Please let me know what you guys run and what you think of it. This is my first gas truck so i am not sure what to look for. It’s a 90 1/2 ton sub. thanks


    mike
     
  2. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    You are running TBI correct ? I would pick a computer compatible cam from Crane or Comp Cams. Something dual pattern that produces torque where a heavy sub can use it, their sites list cams with detailed descriptions . Your exact setup of gears , trans, and stall speed are all factors to pick out a choice of cam. If you used a regular type cam , and without knowing your truck , I would use something like a Comp 268h. /forums/images/graemlins/k5.gif
     
  3. SF87K5

    SF87K5 1/2 ton status

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    I would call the cam company, I am looking fora hydralic roller cam for my K5. I will be calling CompCam and see what they recomand. I sugest you call them and the other companys and see what they recomand.
     
  4. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    I did not know all that. I will be calling as well. thanks
     
  5. 84_Chevy_K10

    84_Chevy_K10 Banned

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    If you're using TBI do NOT get the Extreme 4x4 cam. I had one in the past and it was 111* LSA which is insufficient for a TBI engine.

    Comp has a line of Compucams I do believe that have 113* LSA which will work much better with TBI.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    My *opinion* (and if you believe Desktop Dyno 2000) is that Cranes line of camshafts is better suited to EFI rigs...at least the roller ones I was looking at. Flat tappet? Who knows, check with both for sure.

    Things may have changed, but their selection of cams in the 112*+ LSA range, with more lift than stock, but not crazy amounts, was greater, and the specs of the cams themselves were better, as was output in DD2K.

    Not saying Crane is a better company, just that the cams I looked at, had more effective grinds for my application, than Comp. I'm running Comp Roller Rockers, so that should prove that I have no bias towards either company.
     
  7. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    thanks guys. i am really not even sure what you guys are talking about, i know very little about gas motors. it is my first. Can someone tell me a bit??



    thanks
     
  8. branrat

    branrat Registered Member

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    It would be better to stick with a smaller cam rather than a larger one unless you bump up the compression. The Crane compucam series would work for you. Call their tech line & tell them what you are trying to do.
     
  9. jarheadk5

    jarheadk5 1/2 ton status

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    LSA is Lobe Separation Angle. That's the best explanation I can give; I haven't dug far enough into cam theory to know what exactly LSA is on a cam, and how it affects the motor. Tim'll probably explain for us all.
     
  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    My *opinion* (and if you believe Desktop Dyno 2000) is that Cranes line of camshafts is better suited to EFI rigs...at least the roller ones I was looking at. Flat tappet? Who knows, check with both for sure.

    Things may have changed, but their selection of cams in the 112*+ LSA range, with more lift than stock, but not crazy amounts, was greater, and the specs of the cams themselves were better, as was output in DD2K.

    Not saying Crane is a better company, just that the cams I looked at, had more effective grinds for my application, than Comp. I'm running Comp Roller Rockers, so that should prove that I have no bias towards either company.

    [/ QUOTE ]

    I was actually getting mixed up, it is crane that offers the, "compucam" which is the EFI friendly line.

    I have no bias either, I've used both brand's stuff myself.

    Instead of trying to type out what lobe seperation angle is in words, I'll just copy and paste from the Crane website:

    "What is Camshaft Lobe Separation and how does it affect the engine?

    Lobe separation is the distance (in camshaft degrees) that the intake and exhaust lobe centerlines (for a given cylinder) are spread apart. Lobe separation is a physical characteristic of the camshaft and cannot be changed without regrinding the lobes.

    This separation determines where peak torque will occur within the engine's power range. Tight lobe separations (such as 106°) cause the peak torque to build early in basic RPM range of the cam. The torque will be concentrated, build quickly and peak out. Broader lobe separations (such as 112°) allow the torque to be spread over a broader portion of the basic RPM range and shows better power through the upper RPM. "

    Basically if you were looking at the front of the camshaft and drew an imaginary line through the center of the intake/exhaust camshaft lobes for the same cylinder, LSA is that angle.
     
  11. 89fullsiz

    89fullsiz Registered Member

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    Yep although that is a generalized statement other specs of the cam have just as much if not more to do with the powerband of a cam, it could be said that the rest of the specs actually determine the LSA. Anyways I'm not sure how well an 106 would idle although I'm used to relatively "big" cams in LT1's and LS1's. A 112 on a say 224 duration will idle pretty choppy and it seems would be rough to tune on a TBI setup (just from experience in on a 93 Speed density LT1) 114 or even 116 would idle nicely but then your the cam will peak high and be more "peaky". A camshaft really depends on the rest of your mods and how well your intake and exaust work. I would contact Crane or comp cams and explain what you what and follow thier suggestions.....JMHO
     
  12. Z3PR

    Z3PR Banned

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    I had a bad experence with Crane cams in the past, so I tend to go with Comp Cams.
     
  13. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I was referring more to the, "What is lobe seperation angle" more than anything else.

    As you stated, LSA does factor into powerband but there are MANY more factors that need to be considered besides LSA when referring to a camshaft.
     
  14. 89fullsiz

    89fullsiz Registered Member

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    [ QUOTE ]
    I was referring more to the, "What is lobe seperation angle" more than anything else.

    As you stated, LSA does factor into powerband but there are MANY more factors that need to be considered besides LSA when referring to a camshaft.

    [/ QUOTE ]

    Oh I wasn't trying to critique your input by any means just trying to add too it. /forums/images/graemlins/smile.gif
     
  15. 84_Chevy_K10

    84_Chevy_K10 Banned

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    No critiquing my input anyway, I cut and pasted that. /forums/images/graemlins/thumb.gif

    There are so many factors that go into selecting a camshaft it's insane.

    I dunno how a guy sits at a desk and decides what he thinks you need but he's more skilled than I am.

    As to a, "Bad experience" with a major cam manufacturer, I don't buy it. Bad oil pressure, improper breakin, not using assembly lube, springs that are too stiff? sure. Bad, or soft camshaft right out of the box? I don't buy it at all. Especially from a major manufacturer.

    If I was shopping for a camshaft I'd look at EVERY brand, not just one. There is an idea grind out there for each and every one of us......it just might take you a while and some DD2000 time to find it.

    One day when I build my 4" bore 4" stroke SBC I bet I'll have a fit trying to find a cam that works in an engine that nobody that I've heard of has built before.
     
  16. Thunder

    Thunder 3/4 ton status

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    [ QUOTE ]
    thanks guys. i am really not even sure what you guys are talking about, i know very little about gas motors. it is my first. Can someone tell me a bit??

    [/ QUOTE ]

    READ THIS!
     
  17. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    thanks guys that helped a bit.
     
  18. monte0172

    monte0172 1/2 ton status

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    Comp Cams is based here in memphis and i have a couple friends that work there. call their help line and tell them exactly what you have and what you are trying to do. They will give you lots of options It just depends on how much you want to spend. Good luck!!!
     

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