383 stroker dyno results

Discussion in 'High Performance Modifications' started by 1974blackz28, Aug 12, 2017.

  1. 1974blackz28

    1974blackz28 Member

    91
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    Jan 29, 2010
    Detroit
    I think everyone has the wrong Idea.... I originally dyno'd the car because it doesn't seem to be pulling as hard as my previous setup with a 355 and a lunati 268 cam, It is fast for what it is but not what I think it should be.

    I think the comp 270h cam is definitely my weak point because its such an old style grind that cannot keep up with the newer styles. Also, If I can significantly increase my torque and power input with just a cam swap to take advantage of the rest of the motor, why would you recommend against it?
     
  2. Charlies74Z28

    Charlies74Z28 New Member

    5
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    Aug 15, 2017
    Knoxville, TN
    I am running a full hydraulic roller assembly with floater pistons, Howard rockers and lifters, lunati voodoo series 550 lift cam, ported and flowed aluminum Heads 202 /160 valves, Edelbrock Performer RPM intake, 750 holley vacuum secondary, if i recall it has a .072 in the primary, and .080 or .082 secondary, it was built and run tested by James Grey at greytech. Mine was put on a run stand and dyno tested at the crank and put out 487Hp and 490 lbft torque. Cam makes power between 2400 and 6200 rpm so I shut it down with my MSD box at 6000 to keep from over revving even though the lifters, and the intake are good for 6500rpms. With the Tremec TKO 5 speed I smoke the wheels through 1st, 2nd, and 3rd gears and turn it over hard in 4th mostly due to the 15inch wheels and 245/60 BFG tires that can't handle that much power.
    Car has excellent street manners, but my times are terrible because I can't hook it up.
     
  3. Charlies74Z28

    Charlies74Z28 New Member

    5
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    Aug 15, 2017
    Knoxville, TN
    This is what a roughly 500hp 383 stroker, with factory 373 gears and a new Tremec TKO 600 looks like. I ran out of parking lot before I could hit 3rd gear. At the drag strip I was cheered and was given the best burn out through an 1/8 of a mile.

     
    Last edited: Aug 16, 2017
    stapleszoo, 80sz and Coadster32 like this.
  4. biker

    biker Veteran Member

    Awesome video! That is my kind of fun too. Nice evil chuckle at the end.
     
  5. CasperCasper

    CasperCasper Veteran Member

    947
    84
    Aug 11, 2015
    Generally speaking from my experience a bigger cam, with more overlap and duration, will always trade low end torque for high rpm hp. When you more your max torque higher in the rpm range it is not as good to drive on the street because you wont hit peak torque, in second gear for example, until say 5500rpm. 2nd gear at 5500 rpm is getting excessive on any country road speed limit. Moral of the story is it shifts the torque curve.
     
  6. Coadster32

    Coadster32 Veteran Member Lifetime Gold Member

    1,201
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    Oct 2, 2013
    Milford,CT
    I didn't. I honestly don't know enough about cams to comment on that. You had mentioned an engine swap, which is more expensive than a cam swap, so I posted based on that comment. The only thing I can say about a cam swap, is to beware if your heads/pushrods/valves/springs, etc. would be compatible with your new cam selection. If not, a simple cam can get expensive really quick as well.
     
  7. Charlies74Z28

    Charlies74Z28 New Member

    5
    4
    Aug 15, 2017
    Knoxville, TN
    The cam technology has greatly improved, you can find a cam with good manners on the street that will improve your hp and not kill your torque especially with a strocker they generally makes tons of torque anyway, but if you do go ahead with the swap Coadster32 gave you excellent advise the valve train needs to be considered, as well as your stall converter and rear gear. Still less expensive than an engine swap which would also require a look at your transmission and rear end. The point being I am all for you doing whatever is necessary for you to be happy with the car. Just do your research and look at the total package or you still will be chasing that feeling you're looking for.
    Thanks Biker for your comment.
     
  8. Damon

    Damon Veteran Member

    12,927
    15
    Nov 16, 2000
    Philly area
    SOMETHING is holding that combo back. 308HP on the rollers seems low, even if you were using a stingy Mustang dyno. No way to know for sure (trap speed at the dragstrip is your best un-baised indicator). But SOMETHING is off. Maybe you won't hit 500 crank HP, but 450 with that combo seems do-able.

    I suspect it's in the tune. I'm talking about jets, timing AND maybe inadequate valve springs, if it's laying down at higher RPMs. A combo like that might be "flat" at 6000 RPMs but it should be able to rev to about 6500 without valve float issues. Are you you outrunning the fuel system? Are you just jetted dead wrong? Is your timing maxing out at 25* and costing you 40HP? It could be a bunch of things, none of which you can just ask a question on the internet and get the answer.

    Timing is the easiest thing you can check in your garage with nothing but a dial-back timing light. You need at least 32* max timing above 3000 RPMs (vacuum advance disconnnected). I ALWAYS start by checking ignition timing.

    Valve springs you know if you outrun them because it just "hits the wall" at a certain RPM. Running out of fuel can feel similar but not the same. Outrunning fuel it just "shuts off" at a certain RPM and then comes back to life when you pull the next gear. Valve springs it feels like it just runs out of steam and hangs there at a certain RPM, not wanting to rev higher, regardless of load. Jetting you just play with and see if it wants to be richer, leaner or doesn't make much difference.

    Check one thing at a time. Rule out what it can't be so you know what it MUST be.
     
  9. dcozzi

    dcozzi Veteran Member

    2,183
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    May 1, 2002
    Phoenix, AZ
    No one mentioned the 750 vac sec carb. Since you have a stick shift car, you should try a 750DP. With proper tune, it will be ultra responsive down low and the secondaries are guaranteed to open all the way at full throttle. With 10.5:1 and a stick, you may want to try a larger cam. Maybe something between 280 and 292 adv. dur.
    A couple hundred bucks and some time in the garage will get you more bang for your buck than a new motor and closer to the 450 at the crank you should be able to get from this package.
    I did not remember but, is your ignition in good shape and have headers with 1.75 primaries?
    As usual, Damon makes a good point. Tuning is crucial to get all out of a combo. One thing at a time is great advice too.
     
  10. dcozzi

    dcozzi Veteran Member

    2,183
    31
    May 1, 2002
    Phoenix, AZ
    Let me apologize for being an idiot. You have an auto trans. Still, the double pumper will probably be a better carb.
     

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