Opinions on shift points....RPM

Discussion in 'Competition Camaros' started by 54baker, Oct 30, 2017.

  1. 54baker

    54baker Member

    89
    3
    Oct 29, 2014
    Waverly, ia
    I'm building an 81 full steel, full interior strip car that will be street legal. It has a 392 stroker built from a 4 bolt main high nickel 350 block. quick fuel 600 dp carb. Engine Quest 190cc 2.02 valve iron heads. edelbrock eps intake. 416hp at 5100rpm. 486ftlb of torque at 3700. It has a rebuilt 10 bolt with 33 splines and Ford ends. Full Caltracs front ans rear. 28" drag radials. TH400 w/ Freakshow 4000 rpm flash converter. My plan is to get the chasis set up with this engine and decide if i want to take the plunge into a 427 sbc in the future. Ill try and attach a photo of the dyno sheet. (Btw, this looks a little dif than the dyno I posted before. This is the final pull).
    My question is, what rpm would you set shift points at? I was thinking 400 to 500 above peak hp? Your thoughts?
     
  2. 54baker

    54baker Member

    89
    3
    Oct 29, 2014
    Waverly, ia
    Found this site interesting. You plug in your numbers and it gives you this.... Screenshot_20171030-175548.png
     
  3. mrdragster1970

    mrdragster1970 Veteran Member Lifetime Gold Member

    .

    Obviously my stuff is a completely different animal,
    but I was taught 1000 rpm if the parts can handle it and test different shift points from there??
    Obviously if you have good heads, carb, cam etc etc
    and a cheap ass china crap crank & rods your power band will be above what it can handle without breaking???


    .
     
  4. 54baker

    54baker Member

    89
    3
    Oct 29, 2014
    Waverly, ia
    I will be talking to the builder tomorrow. It was built as a street motor, but figures it would work to get my chassis set up and learn from since this is my first drag car. It has a Scat crank, Eagle SIR I beam rods and Icon forged pistons. Im pretty sure when I talked to him last he had no problems with spinning it 6k or a little higher.... I'm thinking 6k would be a good starting point according to what the calculator showed me. Right on with what you are saying as well. Thx.
     
  5. G72Zed

    G72Zed Veteran Member

    376
    21
    Sep 8, 2015
    Canada
    Looking at your dyno sheet, I would not shift it past anything higher than 6,000 RPM, to loose around 55 HP & TQ in 100 rpm's tells me it's gone into valve float or spring surge or something else, pulled it off quick maybe.

    If you shift at 6k, your dropping 40.3% on the gear spread to 2nd, (2.48-1.48) 6k will recover at approx. 3,600 rpm, right in your tq sweet spot. (pending conv. slip%)

    BTW, the EQ's where nice, but they made 180/200/215/235 cc runners, never saw 190's!! where they ported to 190's perhaps? Either way, with those heads (180 or 200) I would expect to see around 450-465hp if the cam is matched up. Dual planes, especially none partially split dividers can tolerate, and need more carb CFM. JMO
     
  6. 54baker

    54baker Member

    89
    3
    Oct 29, 2014
    Waverly, ia
    I'm pretty sure it's less than 10:1 compression. I'd have to check. It's a custom grind cam. The engine builder designed it for his Elcamino and torque. I'm pretty sure it could've made 450hp with some changes. However..... I'm stuck with it for now. ;) Also, I couldn't find a 190 EQ head either. I'll ask him tomorrow about the heads. I think 6k would probably be max also and he dynoed it with a couple other intakes and carbs. This was the best run. Thx for the reply
     
  7. 54baker

    54baker Member

    89
    3
    Oct 29, 2014
    Waverly, ia
    Screenshot_20170810-160953.png here's what I have to go by other than the builders many dyno run sheets and good memory....
     
  8. SRGN

    SRGN Veteran Member

    181
    49
    Feb 20, 2009
    Central NJ
    I was taught many years ago that your optimal shift point was 10% higher than your peak HP RPM. If your peak is 5100, start at 5600 and adjust from there. I'd find out if you have enough valvespring before taking it too high though. Given the rod ratio in a 392 is around 1.55, I don't think you should be winding it too high anyway.
     
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  9. 54baker

    54baker Member

    89
    3
    Oct 29, 2014
    Waverly, ia
    So here's another dyno pull. Obviously he let off on the other one... Screenshot_20171030-205103.png
     

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