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4/7 swap cams

Discussion in 'The Garage' started by sled_dog, Feb 18, 2007.

  1. sled_dog

    sled_dog 1 ton status

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    Anyone have experience with one of the 4/7 swap cams out there? I think the idea sounds great, and everyone I talk to thinks so as well and wants to try one, but has no real experience with one. Comp makes a Xtreme Energy Solid Flat cam in the 4/7 swap setup that looks like it would be really nice in my Dad's Street/Strip 350. Just looking for any real world experience.
     
  2. 55Willy

    55Willy 3/4 ton status

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    everything i have read up on them is if you are into racing and need every once of power then they are what you want but in a dialy driver you won't notice the benefits.
     
  3. ryan22re

    ryan22re 1/2 ton status

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    Aren't they like mega expensive compared to regular cams?

    Drag racing buddy at work swears by them, but he doesn't have any dyno/et numbers to back it up. Makes the motors sound different.

    Personally, I'd put the extra money somewhere else considering it's not a full on race motor. Perhaps machine work/balancing or upgraded head/main bolts.
     
  4. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    This cam is intended to help remove some harmonics from the engine and make it run a little smoother. They are very expensive and not worth the money unless it is for a full out race car looking for any advantage possible to make any more HP.
     
  5. big dan

    big dan 1/2 ton status Premium Member

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    I thought it would be a cool idea when I first heard about them. most of the ones I looked at were over $400 and the rpm range was something like 4000-8000. I dont think its a good idea after seeing the numbers.
     
  6. ryan22re

    ryan22re 1/2 ton status

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    Pretty sure you can get a street biased cam cut with the 4/7 swap these days, but I think it's still over $300. And probably be a flat tappet cam at that. My vote goes for a hydraulic roller.
     
  7. sled_dog

    sled_dog 1 ton status

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    $240, not terrible in my book. For a street/strip flat mechanical cam.

    You guys are missing something, I didn't mention. The engine is built, used, and run. Was in Dad's circle track Nova for a while.

    Its a 353, fully balanced rotating assembly, full roller rockers. GM Bowtie performance heads, shaved and ported.

    But the cam that is in it was for circle track racing with the 2bbl on top of it. He is looking to have a mean street strip car running on alcohol. As it sits its got almost 12:1 compression. I plan to install head studs and ARP main bolts, a 4/7 swap cam and hit the dyno to see what shes really doing. Other than that there is nothing much I need to do to the engine. Oh that and shave the intake. Old intake wasn't matched well due to the shaved heads.
     
  8. 55Willy

    55Willy 3/4 ton status

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    if thats where the motor is at right now, I'd say throw the cam in there. sounds like you have a pretty mean motor.
     
  9. ryan22re

    ryan22re 1/2 ton status

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    Well then I say go for it.

    I assume this is an E85 build? I've got my mind set on a high comp/blower motor running on E85 (105-106 octane for those that don't know)
     
  10. sled_dog

    sled_dog 1 ton status

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    nope race alcohol build. I don't know nearly enough about alcohol yet, I really need to start learning. My cousin used to race Modifieds which were 358s running 4 barrels and alcohol on steel heads. Hes gone to a Sprint car now. We are going to run one of his old 4 barrels and the same alcohol fuel those cars run on.

    A Firebird that brings a tear to your eye :). The engine used to be run on VP 108, but the cost of fuel is so outrageous Dad wants to try something different.

    Guess I will just be my own guinea pig for the 4/7 swap cam. I'm intrigued by the idea of a SBC that sounds different when rapping out RPMs....
     
  11. ryan22re

    ryan22re 1/2 ton status

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    More than likely methanol. I don't know enough about it to say one way or the other.

    Although I do know that methanol/ethanol/e85 carbs should interchange. E85 would make fill ups a little more friendly.

    What kind of fuel system are you going to run? Carb, efi, manual fuel injection?
     
  12. 81K5GUY

    81K5GUY 1/2 ton status

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    saw on Hot Rod TV last week where they swapped in a 4/7 cam with the same specs of the 7/4 except the firing order swap and gained 20 something hp but they didnt say at what rpm.I imagine it was in the upper rpm range since the idea of the cam is to smooth out air flow(thats what was said on the show)
     
  13. JpEater

    JpEater 1/2 ton status

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    Horse Power Tv did a dyno test on spike a while back. Their dyno test showed a 20 something Hp increase at the crank. Don't remember exact numbers though.
     
  14. sled_dog

    sled_dog 1 ton status

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    never seen an E85 pump around here.

    Carb engine. Electric pump with regulated return fuel system.
     
  15. ryan22re

    ryan22re 1/2 ton status

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    That's odd.

    There are only 9 within 100 miles of your house, but there are 75 within 100 miles of here. There is one about 2 miles down the road from my house. Maybe PA is a little slow to come along.

    Check here:

    http://www.e85fuel.com/database/search.php
     
  16. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

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    From the Lunati website:
    The 4/7 firing order SWAP configuration decreases crankshaft deflection, delivers a smoother torque curve, and aids acceleration. 4/7 SWAP Camshafts also provide an incremental horsepower gain in the engine. 4/7 SWAPS were track tested in a wide variety of applications and all results were improvements over the standard firing order. Dyno results have shown a 3 to 12 HP gain with the SWAP. The only change that must be made to the engine is to swap the 4 and 7 plug wires to reflect the alternate firing sequence. 4/7 SWAP Cams are available in most popular grinds and on custom ground camshafts.
     
  17. bowtiepower00

    bowtiepower00 1/2 ton status

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    Hot Rod or one of the other mags did a direct comparo on a 6500 RPM or so street/strip engine and the difference was under 20HP on a Dyno Tuned engine. If you're revving it higher, you'll see more benefit. Not going to be night and day, but worth it on a dedicated build if you're going for max HP.
     
  18. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

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    I've talked with a couple bracket racers, and they say you can see the diff on the timing slip...... .05 or so, but idles a little smoother
     
  19. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    what is the 4/7 swap cam?
    also when people say that is expensive... I never get it...

    $400 for xover steering
    $500 for rear disc swap
    $xxxx for d60 front and lockers


    so I see the question was will the cam be a good choice... sorry I dont know much about it as I dont even know what the 4/7 cam is...

    I bought the comp cams xtreme 4x4 roller cam and love it.... $275 I think from summitracing.com
     
  20. 79k20350

    79k20350 3/4 ton status

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    Sounds like the benefits are more than just power also. A smoother running engine at low rpms? that nice, smoother torque curve as well...

    I too dont understand how and extra hundred bucks for a cam seems outrageous?:crazy:
     

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