More power out of my 383?

Discussion in 'Engine Topic' started by hutchenc, Dec 22, 2012.

  1. hutchenc

    hutchenc Veteran Member

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    I have a 383 that I'd like to get some more power from. Here are the current specs.

    -2 piece RMS 2 bolt main block, cast crank, PM 5.7 rods, hypereutectic pistons.
    -Profiler 195 Econo ported heads from Chad Speier, 10.6:1 compression
    -222/230 Crane retro roller cam with 1.6: roller rockers (.543/.563 lift)...same cam as is in the ZZ383, but for an older block
    -Weiand Stealth dual plane manifold, Demon 750 VS carb
    -Full length 1 3/4" headers, 3" collectors, 2.5" exhaust all the way with an x-pipe and Borla mufflers
    -MSD distributor, coil, wires, blah, blah, blah

    The car has a 700R4 with 3.73's posi out back. The thing just doesn't seem to have the same power as my little 355 with a muncie does...which is strange because the 355 has the same heads, very similar cam, less compression, and 3.73 posi as well. The 383 has maybe 1500 miles on it btw.

    I'd like to swap in a 4 speed this coming summer...I think that will make it more fun to drive (for me)...but I'm also thinking I want a bigger cam for more power. Will this thing live if I stab a 235 (ish) cam in it? Should I be concerned about the 2 bolt mains? I don't plan to rev it over 6K RPM at all.

    What's a realistic expectation for this thing given the short block?
     
  2. hhott71

    hhott71 R.I.P 11/19/18 Lifetime Gold Member

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    What converter do you have?
    A 3000 stall (with lock up) converter aint cheap, but its cheaper than a 4 or 5 speed swap.
    Also, a badly rebuilt automatic transmission can hold you back by a 1/2 second or better, as can a junk converter.

    28 extra cubic inches is only 25-35 HP and about 30-35 ft/lbs of torque. It's nice to have but it's not a 150 shot of NO2.
     
  3. hutchenc

    hutchenc Veteran Member

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    I have an unknown brand converter that stalls around 2500 RPM. I believe it's a rebuilt 12" unit to be honest.

    The tranny shifts well and has all the goodies that a 700R4 can use (.500 boost valve, Corvette servo, shift kit, etc.). It's a 30 spline input shaft 700R4 as well.

    Honestly, I hate automatics and think they're boring to drive. I'll probably do the tranny swap regardless.

    The car launches well, but it doesn't seem to have the mid-range and certainly not the top end that my 355 has.

    Do you think it could be as simple as having a converter that isn't transmitting the power? If so, that makes a 4 speed swap all the more attractive.

    The cam that's in my 355 is actually a little bigger than the one in my 383 (225/235 at .050). If I put a cam that's 10 degrees bigger in my 383 would I pick up much power? The cam that's in it now just seems rather tame...hardly any lope at all and it idles around 800 RPM no problem.
     
  4. old blue 75

    old blue 75 Veteran Member

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    I would us a cam that is ground on a 106 lca with 230deg. at .050.
    I helped a guy I work with build a 383 like yours except with
    afr 195's his did 522hp at 5900rpm tq was about 510.
     
  5. hutchenc

    hutchenc Veteran Member

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    What sort of power could I gain going to a bigger cam?
     
  6. Gary S

    Gary S Administrator Lifetime Gold Member

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    Just some thoughts.

    You can go to a bigger cam and gain some HP, but it will all be on the top end. Isn't a 383 a long stroke engine? Long stroke engines shine at lower rpms, so a bigger cam may not get you where you want.
    I agree with you that getting rid of the 700R4 and putting in a manual tranny will get you more power. All automatics suck up power getting the "rubber band" (oil) in them tight. A manual tranny will put that power to the wheels.
     
  7. soco200p

    soco200p Veteran Member

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    That's a pretty solid setup you have right now, but 4-speeds always feel faster than autos due to the extra gear.

    The only things I could think of are to go with a slighter bigger cam, and a quality, 10" 3000-3500 stall will wake it up.
     
  8. hutchenc

    hutchenc Veteran Member

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    Yeah I've thought about swapping the converter but man...they are not cheap. I could almost buy a Muncie for as much as some of converters out there.
     

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