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Horsepower estimates anyone?

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  • Horsepower estimates anyone?

    c'mon it'll be fun!

    408 stroker- 351 W block
    Flat top pistons- approx <11:1> compression
    Edelbrock Perf RPM top end
    -Air gap intake, 2.02 1.60 valves, 170 cc intake 60 cc exhaust
    750cfm double pumper 4bbl holley
    matching roller RPM cam, .520 lift, 298/302 adv duration
    roller valvetrain

    along with forged internals, h beam rod, main girdle, stud girdle, etc etc..

    according to what I am buying, it should live right in the 1,500 - 6,000 range and thats where I want it for bracket racing. What horspower should I expect with this setup?
    thanks,
    wes

  • #2
    SAE net or gross?
    sigpic

    Alex Denysenko
    Co-Administrator

    NHRA/IHRA/NMCA member and licensed Superstock driver
    NHRA and IHRA SS/LA & SS/MA National Record Holder 99','00,'01,'02,'03,'04,'05 & '06
    First NHRA & IHRA 289 automatic Superstock Mustang in the TENS 06-99
    First SS/MA in the TENS 04-03
    5 time IHRA division 5 Superstock Champion
    Fleet of FoMoCo products including 88 ASC McLaren Mustang #28

    The Barry of BarrysGrrl

    Quote #1: "I never met a magazine mechanic I liked."
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    www.moneymakerracing.com

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    • #3
      170cc heads are going to choke that thing...big time!
      Ben
      '93 & '97 champion of Central Indiana Dirt Racing Asc.
      C.I.D.R.A.
      __________________________________
      '79 Fairmont 408C/C4 10.50 @ 127
      '70 Mach I 351C 4V toploader
      '07 Mustang GT

      Comment


      • #4
        Originally posted by clevelandstyle View Post
        170cc heads are going to choke that thing...big time!
        Yep! It will be lucky if it makes power to 5500 rpm with those little heads on it. Add to that combo that small cam, and it will make a ton of power down low (especially right off idle), but will probably stop pulling around 5200 or so.

        Big inches + small cam + small heads = no upper rpm power.
        Rob Hetzler
        M&M member since Oct 2000, #773
        Roxboro Dragway 2011 Top ET champion

        My Photo Page

        Comment


        • #5
          11:1 sounds low for a 408 with flat tops. What cc are the combustion chambers?

          BTW those "small" heads should support over 500hp. Not sure what your goal is....
          68 Mustang coupe NMCA Mean Street
          347 NA @3100lbs
          best so far: 10.52@125 with 1.43 60' on goodrich 275-15 drag radials looking for 10.20's!
          67 mustang 11-teens with 351W/C9OE heads and rusted out floor pan
          69 torino gt 351C 4sp
          78 F150 460 running low 14's
          02 powerstroke

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          • #6
            Should be 627.4hp @ 7348rpm

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            • #7
              I just recently picked up a "how to build big inch strokers" book by George Reid and it has that exact build in it..408 with rpm heads and Air gap intake..I have all these exact parts as well so I was curious....The book kinda sucks in my opinion because they don't even tell you the cam specs or compression but here are the dyno results with a 650 VS carb.
              RPM........HP.........TQ
              2000......154........404
              2500......201........421
              3000......245........429
              3500......295........443
              4000......343........450
              4500......384........448
              5000......409........430
              5500......414........395
              6000......399........349
              Here is the edelbrock buildup on a 351 engine(rpm heads,cam and intake with 750 carb)
              2500......161........339
              3000......219........384
              3500......252........376
              4000......311........408
              4500......353........411
              5000......376........394
              5500......397........379
              6000......409........360
              6500......390........316
              Doing some quick math(adding up the columns and averaging) I got these figures
              408 avg hp=316...avg TQ=418
              351 avg hp=298.4..avg tq=374
              So even with the small top end limiting the 408 it still out powers the 351 albeit at a slightly lower rpm range..I wish I had more details on the 408 engine specs but it appears it would be worth it to build a 408 instead of a 351 bottom end..I recently bought a scat 408 kit but I think I'm going to change to an edelbrock vic jr top end instead of the performer rpm top end.
              Last edited by frdnut; 12-10-2006, 12:23 PM.
              http://mustangsandmore.com/memberpages2/frdnut.html
              68 J-Code Sprint,408W 11.59@120.95

              Comment


              • #8
                I took all your specs and entered them into Engine Analyzer Pro v3.3 and came up with these results.

                RPM HP TQ
                2000 158 404
                2500 228 469
                3000 284 488
                3500 337 498
                4000 403 523
                4500 439 503
                5000 442 460
                5500 426 403
                6000 384 333
                6500 304 244
                *Peak HP is 446 @ 4800*
                *Peak TQ is 526 @ 4200*
                According to the graph, the torque falls off drastically at about 4400 rpms and the hp starts to fall pretty good at 4800-4900 and then dies at about 6000 rpm.

                It shows you should have roughly 15.4" of vacuum, so its a pretty weeny cam for that size engine like what was stated above. For bracket racing, it might work good if shifted about 5200-5500 or so.
                1994 Lightning "Pro Street"
                *Old Combo* 408c CHI 3V 225cc Heads, 3v Intake, Dave Storlien solid roller, Rollerized c6, UCC 6,000 rpm converter, Merkl Racing 'brake, AJE k-member front suspension, and Outlaw 4 link with Koni da coilovers.
                715hp and 604 ft lbs @ the flywheel on pump gas.
                6.50@106.63 1/8th
                10.38@126.9 1/4
                1994 Lightning 408c 3v

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