Dyno Results Are In! 1971 All Iron 350

Discussion in 'Small Block Tech' started by MrSony, Jun 26, 2020.

  1. MrSony

    MrSony Well-Known Member


    1971 2 Barrel 350, apparently only 63,000 miles. Car it was from looked pretty nice, so it's believable.

    Stock Bore

    3.0/181 v6 pistons, about .094 in the hole, .042 head gasket. I believe it's about 9.6:1.

    stock rods, reconditioned

    stock crank, .010/.010

    .002 clearances on the dot

    Underdog 350 timing cover, still doing great

    stock heads, surfaced/valve job

    TA DP intake

    EverydayPerformance 17057241 800cfm Qjet, further tweaked by me.

    Hooker 1103hkr headers

    TA HEI, 34* all in by 2700rpm

    TA 310 cam

    2.5" dual exhaust, straight out the back, no mufflers.

    Relatively mild build.

    Made 247hp/274ftlbs to the tire on a mustang dyno. That's within 3hp and 1ftlb of my personal guess, so I'm pretty content with that. This was mainly just a curiosity run, wasn't chasing any particular number.

    Secondaries were opening pretty late, according to the dyno guy as he was standing there watching the carb they didn't open fully until 4300rpm. And I can tell they need to open sooner as well, given the gasoline stains on the air doors. I believe that is the cause for the sharp dip in AFR reading (purple line) that the graph shows.
    dyno2.jpg dyno1.jpg
    Last edited: Jun 26, 2020
    Houmark, Dano, patwhac and 3 others like this.
  2. MrSony

    MrSony Well-Known Member

    And, for comparison, my previous engine (rip) was a very high mileage 3x reringed '70 SP 350 that was bone stock at the time of it's dyno run besides a crower level 3 cam, .042 head gaskets, and that same TA HEI but only 30* of timing, factory intake, manifolds, terrible exhaust with chambered mufflers, etc.

    That combo made 211hp@5003rpm and 263ftlbs@2700rpm.
  3. johnriv67

    johnriv67 Well-Known Member

    This is very interesting to see. Thank you!
  4. alec296

    alec296 i need another buick

    Imagine what big valves would do. And figure static loss thru drivetrain. Of 30-40 hp . So easy 280-290 hp.
  5. MrSony

    MrSony Well-Known Member

    Video from the test:

    patwhac likes this.
  6. knucklebusted

    knucklebusted Well-Known Member

    Aren't dyno plots supposed to cross HP and torque at 5250? Why is this one crossing at 4600?
  7. Mart

    Mart Gold level member

    I'd take the dyno money and put it into go fast parts.....:D
  8. MrSony

    MrSony Well-Known Member

    I think its all 3 variables layered on an incorrect scale, or a glitch. i dont really know. the last run i did 2 years ago the graph was normal.
  9. Reidk

    Reidk Well-Known Member

    I see iowa plates on the car. Wheres the dyno located?
    MrSony likes this.
  10. MrSony

    MrSony Well-Known Member

    Midstate machine. East side of dsm. In between the fairgrounds and firestone plant. That general area.
    Reidk likes this.
  11. MrSony

    MrSony Well-Known Member

    I can confirm this combo is faster than a 2020ish v6 challenger. :D
    I'd post the video but itd be considered exhibit A.
    patwhac likes this.
  12. Reidk

    Reidk Well-Known Member

    Sweet man I know the area pretty well. My wife's from des Moines. What's it cost to use it?
  13. MrSony

    MrSony Well-Known Member

    80 for a one and done but both times I went they Tbh were just curious because it's a sbb so they did a few. Normally its $100 plus more per hour if actually dping some tuning
    I can confirm that a single snorkel air cleaner made less than 3hp in difference in power vs no air cleaner.
    Last edited: Feb 25, 2021
    Reidk likes this.
  14. Waterboy

    Waterboy Mullet Mafia since 6/20

    Very cool!!!
    MrSony likes this.

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