Response on my cam choice?

Discussion in 'Engine Topic' started by Stale Giverhaug, Jan 15, 2021.

  1. Stale Giverhaug

    Stale Giverhaug New Member

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    Just curious to hear what you think of my cam choise.
    Maybe there are better alternatives?

    -1992 Chevy small block 350, factory roller block w/ standard flat top pistons.
    -Vortec heads very lightly ported.
    -Heads prepared to handle up to 0.550" lift by using Beehive springs/retainers/locks from Alex's Parts.
    -.015" shim head gaskets to bump ut the compression a bit.
    -Full roller 1.5 ratio rockers (self aligning)
    - 6 speed T56 manual transmission.
    -4,09:1 rear axle ratio.
    -285/45-18 rear tires.
    -QFT SS 650 cfm Double pumper carb.
    -Car weigths around 2750 lbs.

    -Cam: Howards 183215-14:
    RPM Range:1300 - 5500
    Valve Lift Intake:.495
    Valve Lift Exhaust:.500
    Duration Intake:270
    Duration Exhaust:278
    Duration at 050 Intake:217
    Duration at 050 Exhaust:225
    Lobe Separation:114
    Intake Centerline:110

    -I don't want to compromise low end torque too much, because of the T56 transmission with 0,5 overdrive on 6th gear.
    -I like this cam's range starting already at 1300 rpm's.
    -The 114 degree lobe separation probably kill some top end power(?) but on the other hand it makes for a smooth idle and improved fuel economy on low rpm highway driving.

    -Maybe 1.6 ratio rockers could make a difference?
    According to my measurments during the head work, the maximum valve lift is around .520" on my heads. With 1.6 rockers the lift will be higher than that.
    Even thow Alex's parts say they can handle up to .550" with these parts.
    (Interesting to know what you Vortec gurus think of this?
    Maybe my measurings are wrong?)
     
  2. djorgensen3

    djorgensen3 Veteran Member

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    You can also get +.050 valve retainer locks from Alex's but then you may or may not need longer pushrods also. But both will help with valve lift.
     
  3. ChevyReb

    ChevyReb Veteran Member Lifetime Gold Member

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    Interested in why you want the cam coming in at 1300rpm, especially with a stick unless you are wanting to tow something? Is this a Camaro weighing in at 2750 lb.'s? If so that is really light even is stripped down that seems awful light to me.

    I would think you would want the rpm range up from like 1500 - 5800 or so with the gear that low too. I don't think you are going to have any issues with torque down low with 410 gears. If your heads are flowing good above .500 with the port work I would think with a stick you would be more towards a 278 or 280 duration with .510 to 530 lift if your at or above 9.5 compression ratio. that should get pretty fun to drive. Interested to see some of the builder guys thoughts on this.
     
  4. sandlapper

    sandlapper Veteran Member

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    nice lookin' cam for ~ 10:1 street 350 ... but me thinks a shorter LSA (~ 106* - 108*) will make noticeably more low-end torque. For low-end torque, even 110*- 112* is better than 114* ... everything's a trade-off ... consider what RPM range your street-car spends most of its life.

    each of these four are billet steel and have 112* LSA and are quite affordable; recent additions to summit's house cam line
    https://www.summitracing.com/compare#

    FWIW most of the more affordable rollers are Not billet steel, they are cast (including Howards cheaper rollers). Those 4 above are billet steel.
     
  5. 1980RS

    1980RS Veteran Member

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    A 114° LCA will be better for less detonation than a narrow LCA and the wider LCA cam will make more top end power not less.
     
  6. G72Zed

    G72Zed Veteran Member

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    If your using a true 180* split dual plane, you could/should carb up.

    Actually the opposite, the wider LSA flattens the "peak" and stretches the top end rpm HP and calms down the idle given the same duration.

    I 100% agree with 1980RS on this, but I use the LSA acronym instead.
     
  7. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

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    Honestly - I don't like that cam at all. Those are some LAZY lobe profiles
    For the record, I'm a big fan of wide lobe separations, for the same reasons listed above, wide LSA's spread the torque band while mellowing the idle. Peak torque/HP will be lower, but it doesn't matter. For a streetcar, it's all about average torque throughout the RPM range.

    I recommend Crower 00482LM
    Dur @ .050” Lift: 213°/221° RR: 1.5/1.5 Gross Lift: .505”/.525” LSA: 114°
    Much more aggressive ramp rates should be solid off idle with peak power in the mid-5000 range. It will go to 6200RPM no problem, but you'll be over the peak.

    Don't band-aid a cam with 1.6 rocker arms, get a cam designed with the profiles you want

    The 650CFM carb is on the small side for this
     
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  8. sandlapper

    sandlapper Veteran Member

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    suggest avoid detonation concerns primarily with both proper quench and proper CR; not primarily by cam.
     
  9. sooner

    sooner Veteran Member Lifetime Gold Member

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    The problem with many if not most of the off the shelf step nose cams on a wide LSA is that they were designed to run in the LT1 20+ years ago when the means that we had to tune with was not where we are now in regards to technology. I know this is true with the howards cams, because it says "LT1" on the cam card to every one that they make. Comp is the same way on their wide lsa step nose cams. This is how they ended up offering the wide LSA's in the first place.

    The wide LSA was a band aid to maintain favorable idle characteristics, AKA vacuum signal to intake tract. What you end up with is a small cam that gives up gobs of low and midrange torque and has to rev to match the power that it didn't make in the lower RPM ranges.

    I have 2 small block (383,350) motors today that I put together about 10 years ago using the small cam/wide LSA approach and I absolutely hate the power delivery in both of them. Both will be recammed with a narrow LSA cam (among other things) before this summer. One is EFI, one is carb.

    To each their own, but on a small block that I intend on keeping under 7000 RPM I vow to never run a cam with an LSA wider than 108. Bigger cube big blocks and/or high rpm would be the exception. Torquey tight LSA cams are so much more fun to drive on the street.

    If I want a smoother idle, Ill keep LSA's tight but go with less duration. That's what I should have done 10 years ago.
     
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  10. 1320feet

    1320feet Veteran Member

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    [​IMG]
     

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