Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Cam Choices

Discussion in 'The Garage' started by 91GMCSuburban, Jan 1, 2004.

  1. 91GMCSuburban

    91GMCSuburban 1/2 ton status

    Joined:
    Dec 9, 2002
    Posts:
    318
    Likes Received:
    0
    Location:
    San Antonio, TX
    Guys,

    I need your thoughts on a cam choice.

    Engine Specs:
    350 TBI (with 454 t-body & pre-heater) with vortec heads, GM performance spread bore intake w/ EGR, jet chip, 4L60.

    I don't want a major rumbler, but don't mind a mild lopey idle. I am looking to build for more torque as well.

    Also, I am not familiar with the type of CAM I am suppost to get, so please enlighten me.

    And if I haven't thought of something let me know.
     
  2. bigburban383

    bigburban383 1/2 ton status

    Joined:
    Dec 30, 2003
    Posts:
    1,242
    Likes Received:
    0
    Location:
    Michigan, Royal Oak
    On desktop dyno I got the best results with the Powermax 2030 which is 204-214 duration, .420-.450 lifts. Its good for low end torque and it is supposed to be made for TBI engines. Summit sells it for $150 dollars and thats with lifters. Get small tube (1 5/8) full length headers, that will also help for more torque.
     
  3. Z3PR

    Z3PR Banned

    Joined:
    Mar 30, 2002
    Posts:
    19,217
    Likes Received:
    0
    Location:
    Everywhere
  4. TJS

    TJS 1/2 ton status

    Joined:
    Nov 13, 2001
    Posts:
    179
    Likes Received:
    0
    Location:
    Westport,CT
    Is your block set up for a roller block. If it is a late model block it will have provisions for a factory roller camshaft. If it does the spider and lifter hold downs are all over e-bay for cheap. Also the lifters are there as well too. If you have this block then put a factory LT1 roller cam (again cheap on ebay). I have an older block and I am doing this. It takes more work to get a factory roller cam in an eary block. There is a person on e-bay that sells the plans on how to do this. Hope this helps.
    T.J.
    www.tjsperformance.com
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,979
    Likes Received:
    189
    Location:
    Roy WA
    I can't give you numbers, but if you are trying to make more power, start thinking about having a chip burned as well. If the engines fuel demands aren't met (and they probably won't be perfect with a cam thats different than stock) then you're wasting some power that could be gained.

    Of course the more changes made from stock, (and you have done a lot, with the heads alone) the more noticeable the gains from a "chip" will be, but it never hurts to cheeck what the engine wants. /forums/images/graemlins/smile.gif
     
  6. 91GMCSuburban

    91GMCSuburban 1/2 ton status

    Joined:
    Dec 9, 2002
    Posts:
    318
    Likes Received:
    0
    Location:
    San Antonio, TX
    [ QUOTE ]
    On desktop dyno I got the best results with the Powermax 2030...

    [/ QUOTE ]

    What kind of numbers are we looking at?
     
  7. 91GMCSuburban

    91GMCSuburban 1/2 ton status

    Joined:
    Dec 9, 2002
    Posts:
    318
    Likes Received:
    0
    Location:
    San Antonio, TX
    [ QUOTE ]
    Is your block set up for a roller block.

    [/ QUOTE ]

    Not sure. It is a stock 1991, TBI 350.
     
  8. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,095
    Likes Received:
    144
    Location:
    california
    [ QUOTE ]

    Not sure. It is a stock 1991, TBI 350.

    [/ QUOTE ]
    It's a flat tappet cam then. I have a comp 268H cam with 218 duration @ 50 thousanths, 454" lift in and out. It is a pretty big cam for a low end torque motor especially with a smaller cubed motor. With my 406 it rocks for torque. I am going with 1.6 roller rockers soon with AFR heads that will put it up around 484" lift. What cam you wan't depends on what you are going to be doing with your suburban. If you wheel in the mud and do a lot of towing I would suggest a bigger cam like mine. I prefer larger cams for the extra power and sound that they make but thats me. The comp 260H is a nice cam and is 50 state legal. /forums/images/graemlins/thumb.gif
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,979
    Likes Received:
    189
    Location:
    Roy WA
    A '91 block SHOULD be setup for the roller cam. At worst you'll need to tap the holes for the retainer for the lifter "locks", but I believe by 1991 ALL blocks were cast ready to accept the provisions for a roller cam.
     
  10. TJS

    TJS 1/2 ton status

    Joined:
    Nov 13, 2001
    Posts:
    179
    Likes Received:
    0
    Location:
    Westport,CT
    Yep should have provisions for the thrust plate in the front. I just took apart a 90 TBI block and it had provisions for the thrust plate. As dyeager535 stated you have to drill and tap were the spider goes.
    T.J.
     
  11. 91GMCSuburban

    91GMCSuburban 1/2 ton status

    Joined:
    Dec 9, 2002
    Posts:
    318
    Likes Received:
    0
    Location:
    San Antonio, TX
  12. k5blazerus

    k5blazerus 1/2 ton status

    Joined:
    Apr 22, 2001
    Posts:
    654
    Likes Received:
    0
    Location:
    Bend, OR
    I just stabed a IskyRacing cam in my 350. Its a gm crate nothing to fancy but good power. The cam I got is a 270-280 duration and 465 degree of lift. I lost alittle lowend but it pulls pretty dam hard midrange to highend. All and all I am pretty happy with the cam choice i made.
     
  13. stallion85

    stallion85 1/2 ton status

    Joined:
    Jul 11, 2003
    Posts:
    3,659
    Likes Received:
    0
    Location:
    Cedar City, UT
    I recently put a Crane "Tuck Power" cam in my 350 and am very pleased with the low end torque!! There is no lopey sound /forums/images/graemlins/frown.gif But according to crane it is the best for max towing. I will have a few fourwheelers in the near future and possibly towing a camping trailer. [​IMG]
     
  14. 91GMCSuburban

    91GMCSuburban 1/2 ton status

    Joined:
    Dec 9, 2002
    Posts:
    318
    Likes Received:
    0
    Location:
    San Antonio, TX
    Anybody use lunati?
     
  15. Thunder

    Thunder 3/4 ton status

    Joined:
    Jul 20, 2000
    Posts:
    8,946
    Likes Received:
    1
    Location:
    Northeast Nevada
    I would just go with a mild computer grind cam. Either Crane powermax or Comp cams. Both make good computer friendly cams that your Jet chip should be able to handle.
    If you put in too much cam you will definatly be getting into some chip burning. Even the aftermarket "so called performance chips" are very limited on how much cam you can run. With the mods you have already done you have increased the air flow significantly. Running too big of a cam may cause lean conditions in the fuel curve that may cause engine failure.

    I would also consider getting an adjustable fuel pressure regulator so you can boost the fuel pressure to over 14 psi . The stock settings will prolly be too lean to feed that engine at WOT.

    What size injectors are you running?
     
  16. 91GMCSuburban

    91GMCSuburban 1/2 ton status

    Joined:
    Dec 9, 2002
    Posts:
    318
    Likes Received:
    0
    Location:
    San Antonio, TX
    right now, stock. but I have a set of 454 tbi injectors. The only reason I am not using them is I've heard they are overkill for a 350 setup.
     
  17. Thunder

    Thunder 3/4 ton status

    Joined:
    Jul 20, 2000
    Posts:
    8,946
    Likes Received:
    1
    Location:
    Northeast Nevada
    Yeah the 454 ones will be too much for a 350. The stock ones will work ok if you boost the fuel pressure.
    Because the Vortecs raise the compression ratio. A set of 68 lb hr injectors would work nicely too.
    Re:The cam I would call Crane or Comp cams and see what they recomend. You may be able to use more cam with the higher compression ratio the vortecs give you.
    I like to refer people building TBI engines to this site:
    cfm-tech.com
    There is a lot of good info there on building TBIs They also have a custom chip for the GM Vortec 350HO that may be just what you need.
     
  18. 91GMCSuburban

    91GMCSuburban 1/2 ton status

    Joined:
    Dec 9, 2002
    Posts:
    318
    Likes Received:
    0
    Location:
    San Antonio, TX
    I am considering the 68 lb injectors, but not sure as of yet. Now, if I build a 406 with this TBI setup using the 454 tb and injectors, would the injectors still be to much?

    Also, my heads have been ported and have springs that can handle .500. I think this is overkill for a 4x4 application, but...

    Thoughts...
     
  19. 91GMCSuburban

    91GMCSuburban 1/2 ton status

    Joined:
    Dec 9, 2002
    Posts:
    318
    Likes Received:
    0
    Location:
    San Antonio, TX
  20. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,095
    Likes Received:
    144
    Location:
    california
    [ QUOTE ]
    I am considering the 68 lb injectors, but not sure as of yet. Now, if I build a 406 with this TBI setup using the 454 tb and injectors, would the injectors still be to much?

    Also, my heads have been ported and have springs that can handle .500. I think this is overkill for a 4x4 application, but...

    Thoughts...

    [/ QUOTE ] I would run the 454 injectors with a built 406, mine loves fuel. 400's are like big blocks in a lot of ways especially in there torque numbers and fuel consumption.

    500" lift is a lot for a 4wd but you could get away with it on a 406. I will have 484" lift eventually when I go 1:6 rockers on my 406. A bigger cam near 500" lift will sound great but use a little more fuel then a smaller cam, it will pull very hard in the midrange to upper RPM range too. I don't think a cam like that is very TBI friendly though. I would probably run a cam more like the size of mine which is 454" lift and 218 duration. It's a little big for a 350 but nice in a 400.
     

Share This Page