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    383 cam choice

    I am rebuilding my stroker for the third time and am thinking about a new cam. Motor spec are scat stroker crank, falt top forged coated pistons, roller block, 5.7 rods, holley stealth ram w/30lb injectors, vortec heads w/comp beehives. I had a compcams xr276hr-12 and it pulled like a train after about 3200rpms. I talked to Lunati today and they recommended the 501a6 Advertised Duration (Int/Exh): 288/296
    Duration @ .050 (Int/Exh): 234/242
    Gross Valve Lift (Int/Exh): .530/.530
    LSA/ICL: 110/104
    Valve Lash (Int/Exh): Hyd/Hyd
    RPM Range: 2500-6500
    Includes: Cam Only
    Part Number: 501A6LUN
    Its going in a RCSS K1500, 5sp, 456 gears . should I stick with the comp cam or lunati? need a new one either way oil pump failure made sure of that. Took the last journal apart on cam. Or does anybody else have a better idea for a cam/

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    omg it's loud muddinwolverine's Avatar
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    Re: 383 cam choice

    get on chevytalk.org, ALOT of info on 383s and some serious engine builders
    '87 Chevy K10 Scottsdale, 454, 10in susp, 3in bod, 42in tsls, sm465/np205/d60/14bff
    '05 R6 full Arata exhaust, PC3, quick shifter and some other stuff
    '90 S10, 4.3l, the ugliest POS I've seen in a long time

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    onthethreshold
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    Re: 383 cam choice

    Have talked to Lunati reps several times,it seems Comp always comes up with the better choices.just hit there website and type in all your info and they will get back in a day or so.

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    Re: 383 cam choice

    Just built a 383 for my RCSB. Made 530 horse. AFR 195 CC heads 75 cc domes, Flat top SRP's, Comp Cams XR286R.

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    -Jeremy XLR8N's Avatar
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    Re: 383 cam choice

    That's a lot of cam. . .

    What size tires are you running?
    Quote Originally Posted by Xander Berkeley
    I'd better make hay while the sun shines.

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    Re: 383 cam choice

    why 5.7" rods and not 6"?
    2003 GMC Sierra RCSB 1500 2wd, 5.3L, 3.73s w/ g80 locker

    Stock 98 C1500 RCLB Vortec 305

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    Re: 383 cam choice

    didnt do enough research the first build and thats what I got, nothing wrong with them so why throw them away.

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    Did someone say ponies? The Fiddle's Avatar
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    Re: 383 cam choice

    OP: How high are you going to be turning this engine?



    Quote Originally Posted by KTMRACER View Post
    why 5.7" rods and not 6"?
    Unless he ventures into the 6000+ rpm range there won't be much difference.
    2015 Sierra 1500 Elevation Edition. "So impossibly black!"
    2005 Pontiac GTO LS2/A4. So fast it's gone now.
    1999 OBS K1500 Black Bear tuned 383 Z71. 2" rear blocks, Hankook MT's. Still around.

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    Re: 383 cam choice

    maybe 6200, but it will spend alot of time in the 4500 to 6200 range.
    164 views on 0 reply's on chevytalk.org
    Last edited by tommey66; 02-12-2011 at 05:48 PM.

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    Large Marge sent me SUBURBIAN's Avatar
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    Re: 383 cam choice

    Tommey,

    I'd like to help you pick the BEST cam for your setup... you say it really came on at 3200 rpm, right? Where did you feel it backing off on the top end...where did it "nose over"?

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    Re: 383 cam choice

    It didnt feel like it nosed over at all. Pulled my factory tach right up to 6 and seemed like it wanted to go more, think my 411 pcm is controlled at 6000.

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    Re: 383 cam choice

    That is what I thought, but I wanted to hear it from you. You need LESS cam, not MORE. If you build up your engine right, especially for street builds, you want the MOST operating range or power band you can create. That cam wants to work well over your tolerated RPM level....say 3000 to 6500 or higher. You should want a cam that will come on at 2000 or so and pull like 3 locomotives right up to 6000. Doesn't this make sense?

    If you agree, we can get into cam specs.

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    Re: 383 cam choice

    Quote Originally Posted by SUBURBIAN View Post
    That is what I thought, but I wanted to hear it from you. You need LESS cam, not MORE. If you build up your engine right, especially for street builds, you want the MOST operating range or power band you can create. That cam wants to work well over your tolerated RPM level....say 3000 to 6500 or higher. You should want a cam that will come on at 2000 or so and pull like 3 locomotives right up to 6000. Doesn't this make sense?

    If you agree, we can get into cam specs.
    X2

    The old saying is that you can spend a ton of time researching just the cam you think you need ..and then buy the next size smaller, really does hold true (and maybe two sizes smaller ).

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    omg it's loud muddinwolverine's Avatar
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    Re: 383 cam choice

    sorry about the chevytalk bit, I should have just sent a link
    lots of 383 info
    lots of reading but an insane amount of info
    '87 Chevy K10 Scottsdale, 454, 10in susp, 3in bod, 42in tsls, sm465/np205/d60/14bff
    '05 R6 full Arata exhaust, PC3, quick shifter and some other stuff
    '90 S10, 4.3l, the ugliest POS I've seen in a long time

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    Re: 383 cam choice

    I agree, I want it to pull like 3 freight trains. Lets get into cam numbers.

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    Large Marge sent me SUBURBIAN's Avatar
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    Re: 383 cam choice

    Good. You've made the first step, to quit relying on cam salespeople to pick the heartbeat of your sbc for you. All they are is monkeys with computers in front of them..charged to sell cams. They use buzz words, and over cam engines DAILY.

    What we know...

    The XR276 was too much cam. 276/282 adv, 224/230 @ .050, on 110 LSA, with ICL of 106. You say it came on at 3000 or so, and pulled to well over 6000. The comp website rates that cam at 1900-5600. It is very hard to judge numbers like that, especially since you're running more displacement.

    You need a 110-112 LSA, and to keep the duration numbers in the 2-teens/2-twenties. I suppose for your heads, a split pattern cam will be ideal...to compensate for the exhaust side inefficiencies of the vortec casting. I do not suggest that anyone use comp cams in any engine. Only from lessons learned the hard way. Especially roller cams.

    You want off-idle barn-pulling torque. You'll get that from a small cam, but not so small that the cylinder pressure is so high that it pings itself to premature demise.

    It is best if you shop for some cams yourself. Go to the summit racing website, filter out everything until you're looking at only sbc roller cams on 110 to 112 LSA's. Remember that the actual operating ranges listed are for 350 cid engines, not stroker sbc's. See what you can come up with, and post back here.

    Here's one.. http://www.summitracing.com/parts/ISK-201272-282/

    And another... http://www.summitracing.com/parts/LUN-60121/

  17. #17
    Did someone say ponies? The Fiddle's Avatar
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    Re: 383 cam choice

    Quote Originally Posted by SUBURBIAN View Post
    I'm running one step under that one:

    http://www.summitracing.com/parts/LUN-60120/


    In the 383, I love the off idle torque.
    2015 Sierra 1500 Elevation Edition. "So impossibly black!"
    2005 Pontiac GTO LS2/A4. So fast it's gone now.
    1999 OBS K1500 Black Bear tuned 383 Z71. 2" rear blocks, Hankook MT's. Still around.

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    Large Marge sent me SUBURBIAN's Avatar
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    Re: 383 cam choice

    Tommey,

    This fiddle cat here has a REAL strong stroker sbc. He is running a cam smaller than the one that I showed you. See? Small cams are where it's at.

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    Re: 383 cam choice

    On Comp's free cam quest download there is a dyno feature and you can compare the cams torque curves - it's fun and revealing too.

    Build a torque monster, I know...it's hard to compromise sometimes (and that's why you build a larger engine - less compromise).

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    Large Marge sent me SUBURBIAN's Avatar
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    Re: 383 cam choice

    Sure, that's fun. Those things are real tough to isolate single variables though. Don't ever expect to make the numbers that one of those things quotes either. There is more value in matching up parts for an excellently optimized and balanced package than there is in picking a cam based on some marketing team's dyno claims. What kind of rings are in a dyno test mule? Operating temp? Exhaust setup (if any), induction setup, etc, etc, etc. Small cam, big torque. There are a few people on FSC that get it... join us.

    I hate to quote a ford guy, but...

    horsepower sells cars, torque wins races.

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