Does this motor have any more potential?

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    Author Topic: Does this motor have any more potential?  (Read 1295 times)

    Offline loco340cuda

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    Does this motor have any more potential?
    « on: May 09, 2007 - 04:12:06 PM »
    I had a 417 stroker built and dynoed and wanted your opinon if you think with some tuning I can get more performance out of this motor.

    I have attached the graph so you can see how it performed on the dyno with open headers and zero tuning of carb and timing (.i.e just put carb on out of the box and set timing to 15deg initial).  The dyno run is engine out of the car.  The engine was fired up for break in and then he did a couple of pulls to get a baseline of the build.

    Here is the motor's spec's:

    -340 stroked to 417
    -eagle forged 4" crankshaft
    -venolia custom forged pistons
    -9.5:1 compression
    -stock 'X' heads with 2.02 valves (no porting)
    -mopar 484 cam (241int/241ext with .484int/.484ext 108lsa)
    -Edelbrock RPM airgap intake
    -Holley street Avenger 770 carb
    -FBO ignition with distributor that was curved for old 340 engine with no vacuum advance (currently getting distributor re-curved for new setup)
    -This is a 4-speed car

    Now, I just got this engine back from the machine shop so I'm not going to switch out any of the parts but I was wondering if there are some things I can do to tune this motor to get more performance out of it.  I think the performance is a little low and I would like to hear what you guys think, can I tune this motor for more performance?
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    1970 Cuda 340 4-speed - now stroked to 416ci (SOLD)
    2017 Mustang Shelby GT350


    Offline Chryco Psycho

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    Re: Does this motor have any more potential?
    « Reply #1 on: May 09, 2007 - 11:29:33 PM »
    seems low to me as well , I always find 15RWHP or more tuning on a dyno even after tuning off the dyno so tuning it properly will show some gains for sure
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    Offline Projectmopar

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    Re: Does this motor have any more potential?
    « Reply #2 on: May 10, 2007 - 12:41:21 PM »
    You should be developing more power than what's shown with being a stroker I would think?

    I have a "stock eliminator" motor that dyno's at 431 horses @6100 RPMs (by the way its for sale).

    Block: Mopar 340 block (water jack filled)
    Deck Height: 9.00”
    Bore: 4.040”
    Stroke: 3.31”
    Crank: Mopar Forged (stk .013/.010 mns,.020 rds)
    Rods: Mopar HP
    Pistons: Badger, 10.5-1 comp.  Tool steel pins.
    Rings: C&A file fit
    Oil Pan: Mopar 6 quart
    Oil Pump: Mopar Performance
    Pickup: Mopar
    Damper: Fluidamper
    Balance: Internal
    Camshaft: Mopar 256/265 @ .050 camshaft
    Lifters: Schubeck lifters
    Pushrods: Mopar HP
    Timing Chain: Mopar HP
    Timing Cover: Mopar
    Water Pump: Mopar HP
    Head Gaskets: Fel Pro 1008
    Cylinder Heads: Mopar stock CC heads
    Valve Springs: Mopar HP (180 closed X 300 open)
    Retainers: CV Products Chrome Moly
    Locks: CV Products Chrome Moly
    Seals: Fel Pro 11/32” Rubber         
    Seat Cups: None
    Rocker Arms: Mopar HP
    Valve Covers: Mopar chrome covers
    Intake Manifold: Mopar Thermoquad spread bore
    Manifold Gaskets: Mr Gasket #307
    Carburetor:  * Thermoquad (750 CFM) Carb.
    Distributor: Mopar HEI ignition
    Spark plugs: Autolite AG-52 gap@.045

    I would talk to your machine shop about what other options are available to help pump out more ponies. I'm going to my machine shop we use tommorrow and will ask what they think or may suggest for you.
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    Thank you for your time

    Barry Conner

    Offline Chryco Psycho

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    Re: Does this motor have any more potential?
    « Reply #3 on: May 10, 2007 - 12:51:20 PM »
    Just timing a carb tuning should get you 25 hp
     nothing you listed in your combo jumps out as being a bad choice although the heads will not make a Lot of power
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    Offline HP2

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    Re: Does this motor have any more potential?
    « Reply #4 on: May 10, 2007 - 02:38:15 PM »
    Playing with timing and carb tuning should get you some more. Your engine and intake combo would take a lot more carb, imo, but your heads won't so it would be a waste to dump more cfm into them. Stock X heads with no porting will want more timing to burn across the chamber but airflow in these isn't stellar.
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    Offline loco340cuda

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    Re: Does this motor have any more potential?
    « Reply #5 on: May 10, 2007 - 03:22:41 PM »
    Thanks for the feedback guys.  I was suspious of the heads as being the bottleneck, I just didn't really think that it would make that much of a difference.  Next year I will invest in some Eddy heads and maybe another cam.
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    1970 Cuda 340 4-speed - now stroked to 416ci (SOLD)
    2017 Mustang Shelby GT350

    Offline Chryco Psycho

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    Re: Does this motor have any more potential?
    « Reply #6 on: May 10, 2007 - 03:52:16 PM »
    or just get a set of 308 castings , ported even with small valves you will get a 60+ hp gain [40+RWHP]
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    Offline SuperDave

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    Re: Does this motor have any more potential?
    « Reply #7 on: May 10, 2007 - 07:24:07 PM »
    Sounds like a great engine combination.  My recommendation.  Finish breaking in the engine, then do a power tune on a dyno.  You may be surprised at the difference this will make.  Also ... was the camshaft install correct for the power...did the front pully get installed in the proper position for the power band you are looking for?  (how many keys were in the timing chain cam gear...this will tune the cam for the perfomance needed).  Check a local hot rod shop for the details. 

    First recommendation after that...port the exhaust ports to match the gasket...don't go in much over an inch.  Second recommendation...port and polish.

    The 340 in my cuda gets 350 hp to the ground with 323 gears and a 833 4 speed.  RPM air gap, X heads, Edelbrock 750, 1 3/4 inch exhaust and a good cam.  Ignition is a Crane Digital MSD box. Try a power tune.
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