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building hp and torque without a huge cam

Discussion in 'The Garage' started by COCHEV, Jul 22, 2002.

  1. COCHEV

    COCHEV 1/2 ton status

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    been checking out some of the gm crate motor and they are making decent power and torque- 400bt lb range with very mild cams. so obviously heads are where its at. can stock chevy heads be ported to flow as good as say some torquers or sportsmen IIs? or would it cost just as much as buying aftermarket? i think that 400+ ftlbs out of a small block is pretty good. the zz4 makes this with only a 208/221 cam. any one have anything to add to this- personal building experience??
     
  2. BigMac

    BigMac 1/2 ton status

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    my buddy that an engine building nut is swearing by the vortec heads...... he claims 30 hp gains over 202's.
     
  3. Thunder

    Thunder 3/4 ton status

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    The crate GM 350 HOs all come with Vortec heads. The cheapest way to go if you are building a engine is just to buy some from GM. They are less than 500 for just the heads. They are a lot cheaper than aftermarket performance heads.But you will need a intake manifold to fit the heads.
    Or you can get a whole kit that includes heads, Edelbrock manifold, rockers, gaskets, bolts ect for around 700.00
    Heres more info
    vortec heads
     
  4. COCHEV

    COCHEV 1/2 ton status

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    i've been checkin out the sportsmen II heads. i know they are more expensive but still cheeper then most aluminum and allow for more lift. they seem like very veristile heads. check em:

    sportsmen II
     
  5. BigMac

    BigMac 1/2 ton status

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    for wheelin I prefer Iron heads to aluminum. My buddy swears alluminum has come along way, but the warped head horror stories are still fresh in my mind.

    I shy away from aluminum because any overheating probs could spell doom for them. I trust iron to be nice an stable. Heavy maybe, but stable...
    There are more high performance heads out there, but the vortecs are supposed to be perfect for low compresion high torqe aplications.. and affordable...
     
  6. Thunder

    Thunder 3/4 ton status

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    I think iron heads are better for trucks too. After all K5s weigh over 5000 lbs. The few pounds aluminium heads save aren't going to make little if any difference in your performance and seem like a waste of money that could be better spent on mods you will get more out of.
    Personally I would love to have a set of Vortecs on my K5. They are designed for, and work best in trucks. I dont think you will find heads anywhere that will give more bang for the buck than Vortecs
     
  7. BorregoK5

    BorregoK5 1/2 ton status

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    I have to agree on the preference for Iron heads on the full size 4x4's. Vortecs sure get good reviews but I haven't run them yet (thinking about it still). Fact is that if everything was equal the cast iron head will make more power than an aluminum head. The cast iron head doesn't absorb heat from the combustion process as fast at the aluminum head. Therefore more heat is available to push the piston down. The way to get back the lost horsepower is to up the compression on the aluminum head. Typically you can run about a half to full point more compression with an aluminum head over the cast iron without running into detonation. But in the case of resisting overheating for whatever reason, got to go with the cast iron.
     
  8. bablazer73

    bablazer73 1/2 ton status

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    steel heads yes. BUT one thing people are overlooking is the airflow of a head MUST match the R.P.M. that you plan to run. If you port out heads or buy heads with larger intake runners and use them for a lower rpm engine, maybe an engine that runs to 5,500 only. then you will hurt the engine torque. When runner size is increased, velocity will suffer at low rpm. slow moving intake air can cause the fuel to turn back into droplets instead of mist and cause all kinds of running problems at low R.P.M.s. If you need heads or yours need alot of work. check out world products S.R. torquer's small ports all new castings with valves for the same cost of rebulding the average garbage head!! What RPM do you plan to run?
     
  9. COCHEV

    COCHEV 1/2 ton status

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    not sure about my build up yet, just hoping to get some general engine discussion going.

    so maybe if you went with smaller runners and valves and had a cam with a good deal of lift but shorter deration (might have to go with a roller setup) to keep vac high. desent lob separation too. might be a good low end torque combo. eventually it seems you reach a point where you need more flow to get more hp and ft lbs. then the torque range startes to creep up in the rpms.
     
  10. chulisohombre

    chulisohombre 1/2 ton status

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    i got the 2.02 heads on mine and also want more torque.i have great high rpm power but when i wheel there is no need for power.i need a cam that can handle the 2.02 for more torqe.i was told to get a longer duration medium rv cam to help the torqe factor.i still am trying to figure exactly what i need also.so i will also be watching this to see where it goes.
     
  11. BigBurban350

    BigBurban350 1/2 ton status

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    Heads with large valves, and a long stroke crankshaft pushing bored pistons. Larger intake and exhaust will help too.
     
  12. bablazer73

    bablazer73 1/2 ton status

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    everything depends on the "real" plan for the engine. what rpm do you need your torque. 4x4's need torque, actual hp is not the main concern, just a result of where you want the torque. I am running a 454, roller cam,valve train all set up for 5,200 rpm. and i also stayed with those "garbage" small port truck heads! increasing the intake velocity overall, which increases the torque at lower rpm's. one must really plan the engine for the real world need. I have seen many people "throw" good performance parts on an engine and even some high dollor trick parts and still have a slug of a car or truck. my brother and i put a 70 mustang together, spare parts mostly. a 351w from a 72 ltd with the 2bbl still on it. mild engine stuff, cam, intake, headers, bolt on stuff. nothing trick.car would consistanly run 13.30. so many people couldn't believe that we had what we had!! no 4 bbl? we got accused of running nitrious! it was just a well plan out engine using the best combination of cheap parts!
     
  13. COCHEV

    COCHEV 1/2 ton status

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    so what kind of lift are you running with your roller cam. is it a short durastion, high lift like i mentioned above? that would make sense for a good low end torque motor. as for the small valves and runners- this is why people but the 305 heads on 350s. plus the bump in compression helps. i have a set of 58 cc 1.84 valve 305 heads that i am going to try out on a 350 to see if i like the torque.
     
  14. lizard

    lizard 1/2 ton status

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    The only heads for a truck are world s/r with the 1.94 valve. Add a hydraulic roller with around .480 lift and 225@.050 and you hit the magic. a .480 is the mildest cam I will ever see...

    Course that combo only works here in Florida with 99% humidity /forums/images/icons/wink.gif
     
  15. bablazer73

    bablazer73 1/2 ton status

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    sorry it took so long to reply, I wasn't home and couldn't remember cam spec's! the cam I am running is a comp cam hydrolic rollor. intake lift .510 duration 270. exaust is .510 and 276. cut on a 112 seperation.
     
  16. EDdaTREE

    EDdaTREE 1/2 ton status

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    Try www.paceparts.com they have an 800 number and they are the biggest shipper of crate motors in the country. They are said to be really helpful on advice.
     

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