difference between these two cams?

Small Block Mopar Engine

  1. 999yards

    999yards Well-Known Member

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    What would the noticeable (felt) difference between these two cams be?

    Engine/car Specs:

    car weight 3K? 1966 Barracuda

    Tire size 26" sure grip 3.73 727 trans Have not picked out converter yet

    Engine 408 stroker 10 to 1 compression. Nice old Street Dominator (thanks Rumblefish). Holley 950 dp mechanical secondaries. W2 heads offset roller rockers 1.5 ratio. 2.08 intake 1.65 exhaust forgot the cc's but they were milled down just a tad. Econo heads

    1-5/8 stepped to 1-3/4 fenderwell headers Hedman.

    The two cam recommendations so far. forgot to add this will be a hydraulic roller

    Lunati 243-251 @.50 560-565 110ls 106

    Bullet. 236-245 @.50 574lift 110ls 106

    Thanks
     
  2. lead69

    lead69 hopeless car junkie

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    With the cubes I would go with the lunati,I am not sure of your intentions or h.p. goals but given the rest of your components thats the smallest cam I would use.
     
  3. moper

    moper Well-Known Member

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    It's hard to say with the info given. The Lunati seems a little fatter but in my opinion the Bullet may be a better lobe. Which lobes are used for the bullet one?
     
  4. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    You'll never feel the difference.
     
  5. 999yards

    999yards Well-Known Member

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    I have no idea.

    RustyRatRod, that's what I was wondering. I just don't know how far those cams are apart in the seat of the pants feel. They don't seem too far apart but I don't know if this is a case of a little is a lot.

    Some one asked about intended use. All I can say is I'm building a street car to haul ass but I'm not looking for every last .01 of a second out of it either.

    So if I'll never feel the difference I won't worry about it Thanks very much.
     
  6. K.O. SWINGER

    K.O. SWINGER Meeting in the alley since 1976

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    with the heads you have my knee jerk would lean bigger a little more hp :-k potential. lunati
     
  7. AdamR

    AdamR Big Member

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    The bullet seems a bit short on duration for a 4" crank
     
  8. 999yards

    999yards Well-Known Member

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    What kind of issue could that cause. Less scavenging of the exhaust? Or maybe if I decide to put a 100 shot on it one day it would fall below what I need?

    Maybe I better call Bullet after more intel (from you guys) and discuss further.

    I really appreciate every ones help. Having read all I could about cam design before I posted is helpful but having practical guidance from experience is the best help.
     
  9. moper

    moper Well-Known Member

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    It all depends on the lobe shape - and duration at .050 doesn't tell enough. I'd put a smaller Bullet lobe ahead of a Lunati. Bullet's got some great stuff and there are lobes with similar duration at .050 that carry a lot more duration towards max lift. Some have special ramps to keep the valvetrain more stable with bigger areas under the curve. Saying they are identical is like saying a cheeseburger is the same at MacDonalds and Ruby Tuesdays because they both have cheese and beef.
    With those headers I don't think you'll have an issue with the exhaust emptying the cylinder. But I do think you're leaving some power on the table and not getting anywhere near into what the heads can do for you. Those grinds will be great mild cams for you.
     
  10. AdamR

    AdamR Big Member

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    Mc Donalds burgers dont have beef in them !

    Bullet is selling the old Ultradyne grinds now arent they ?
     
  11. JoeDust451

    JoeDust451 Well-Known Member

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    Roller cams have more area under the curve then FT cams, this produces power, That being said, I'd lean more towards the Bullet grind, Bullet has a great reputation when it comes to selecting cams for your needs, Now for instance, If you went with a FT hyd. to produce the same power as the Bullet Roller, you'd need a good 8-10* more dur, @50, so that would be a cam around 245/255 @50, thats a healthy cam wouldn't you think, The Lunati your talking 253/261 @50. This is why you see Roller cams with lesser Dur. #s vs. FTs & there showing the same RPM range, don't let that throw you off. That Bullet cam will see 6500 all day long.

    My choice would be the Bullet, You'll be very surprised at the power it lays down, even with a 4" stroke.
     
  12. 999yards

    999yards Well-Known Member

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    Yes I saw something about ultradyne on their site. So they are mild cams? That's not want I want. I told the guy I wanted something bad ass. Guess he missed that part.

    Moper, what specs should I give to Bullet. I do want to maximize the potential of what I have.

    Thank you
     
  13. 999yards

    999yards Well-Known Member

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    Joedust451, You say lean more toward the Bullet. Are there any changes you would make to it or do you mean lean over and get your wallet out quick cause it sounds perfect.
     
  14. JoeDust451

    JoeDust451 Well-Known Member

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    I say call Bullet & talk with them, If they say yes on that cam, break out your wallet, I'll bet anything he agrees with what i said & that will be all the cam you'll need for a very nice street car & plenty of power with your combo.
     
  15. JoeDust451

    JoeDust451 Well-Known Member

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    I'd go with a 1.3/4 longtube or fenderwell, Those 26" tires might be a handful with that much torque, 28" would be better for 3.73 gears & 4" stroke.. Call & talk to Kenny at PTC converters, I would go with a 9.5", he can/will hook you up for a very good price. I like the M-1 single plane on the BBs.
     
  16. 999yards

    999yards Well-Known Member

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    Thanks man I will.

    Already bought Hedman fenderwell 1-5/8 to 1-3/4 stepped tube headers. Had to buy them for a 67 LA head and cut the flange off to weld a W2 flange on so the 1-5/ 8 length will be shortened some due to the width difference between the 67 and 66

    I figured I will need to work on traction next. There are 2" aluminum spacers between the axle housing and springs. I don't know anything about that but it seems like if I take those out I will have enough room for some 28" tires. Prob need some slide on traction bars too.
     
  17. JoeDust451

    JoeDust451 Well-Known Member

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    Slapper bars can work good if you know how to dial them in, Cal-tracs are the ticket these days, if you go that route make sure you use the Mono springs, I made the mistake of using my old worn out multi leafs, a big no-no.
     
  18. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    This is getting WAY too complicated. Cams (roller or otherwise) are much like carburetors. When in doubt, choose the smaller one, you will be MUCH happier with that instead of one that's too big. It really is that simple. But as I said before, I don't think you will ever know the difference. We can bat around lobe shape, opening and closing ramp rates, how big the flux capacitor is and on and on, but the question is a simple one and deserves a simple, non confusing answer.
     
  19. moper

    moper Well-Known Member

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    Yes they do - just not parts of the cow we'd normally associate with eating...
    Bullet should have acces to all of Ultradyne, yes. As far as I'm concerned they are one and the same, although the Bullet stuff has more recent engineering in them.

    As far as simple answers - if that were the case everyone would still be using lift and total duration to choose cams. So I took the path of he's gotten some info, enough to know duration at .050 is important, and wants to know more in order to choose. Sorry for complicating it so much.
     
  20. 999yards

    999yards Well-Known Member

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    Moper not complicated to me. Just not experienced in such matters. And yes I did want to know approximately when or if the difference in duration would be felt compared to the difference in lift and not just seen on a dyno print out.

    I did learn that lobe profile was also a characteristic to consider when comparing like durations. Not am I only here for advice but to learn more as well. I do appreciate all input.

    Thank you
     
  21. moper

    moper Well-Known Member

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    Another thought - Making good horsepower (or overall power) is not just the power you're trying to create. It's about minimizing the power that is required to keep that crank turning, and the rpms it's capable of reaching. More rpms will always equal more horsepower because there's more firing events per minute right up until valve control or airflow is maxxed out. You could have the same lift, total duration, and duration at .050, and still have a bit more duration at .200, but the lobe is shaped more like a square than a triangle, so the spring required is much stiffer in order to maintain valve control. Those differences can be significant, and the power enough to measure and potentially feel.
     
  22. 999yards

    999yards Well-Known Member

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    Now that I can visualize, great explanation thanks. However, it also explains why I better call them back and include the springs for that cam and new roller lifters, which I ordered this am. And again thank you
     
  23. replicaracer43

    replicaracer43 Grumpy Old Man

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    I am wondering how you plan to bolt a rectangular port LA intake on to a W2 head?
     
  24. 999yards

    999yards Well-Known Member

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    Lol. I'm not. I'm going to have to swap flanges out.

    Thought for a minute you were asking about headers. The street dominator I have is for a W2 with oval ports.
     
  25. lead69

    lead69 hopeless car junkie

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    There is a alot to picking a cam,the bullet obviously has some agressive ramps to be at .574 lift with a 236/242 @ .050 duration requiring at least the same valve spring or more as the lunati.It obviously has a bit less duration at .050 but as moper said it probaly makes it up-or more at .200.I liked the lunati initially because it looks to be slightly less agressive but would behave similar in your build but since you want a hot street car the bullets probaly the best bet.There are always two ways to skin a cat but if I can get similar performance between to hydraulic rollers but use less valve spring/lighter on the valve train with one thats the one I want.
     
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