71 350

Discussion in '1967-1972' started by 74X4Burb, Sep 14, 2004.

  1. 74X4Burb

    74X4Burb Member

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    the 350 engine in my 71 is missing on the no.1 and 3 spark plugs and uses oil like you wouldent believe. havent compression tested it yet, would this be a good place to start? the spark plugs and wires are new but that dident help at all.thanks.Karl

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    Last edited: Mar 16, 2011
  2. tech1

    tech1 Member

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    i am willing to bet money that your valve seals are not in the best of shap you may want to get your heads checked out and have those notoriously bad valve seals repalced
     
  3. 74X4Burb

    74X4Burb Member

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    Last edited: Mar 16, 2011
  4. 72cheyenne

    72cheyenne Guest

    HELLO KARL,

    SORRY TO HEAR THAT YOUR SMALL BLOCK IS SICK.
    #1 AND #3 ARE ADJACENT CYLINDERS, AND IF BOTH ARE MISSING SUSPECT HEAD GASKET TROUBLE. HOWEVER WITH OUT PERFORMING A COMP. TEST AND A CYLINDER LEAKDOWN TEST IT'S JUST SPECULATION.
    A FEW QWESTIONS THOUGH.
    1. HOW MANY MILES?
    2. EVER OVERHEATED?
    3. WATER IN OIL?
    4. OIL IN WATER?
    5. HOW WERE PLUGS FOULED? FUEL? OIL?
    TO KNOW FOR SURE PULL THE HEAD AND INSPECT THE GASKET.

    GOOD THINGS,

    BRANT.
     
  5. 74X4Burb

    74X4Burb Member

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    As far as I know it has 185.000 miles, yes it over heated pretty bad,(the belt came off at a about 11:30 p.m. and I dident see it),never had any water in the oil or vice verse,the plugs were fouled really bad carbon covered the entire electrode.Thanks.Karl

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    Last edited: Mar 16, 2011
  6. 72cheyenne

    72cheyenne Guest

    HELLO KARL,

    O.K., ONE THING I SUGGEST IS TO DO THE COMP. TEST ON BOTH CYLINDERS ONE AND THEN THE OTHER. REMEMBER TO HOLD THE THROTTLE ALL THE WAY OPEN AND CRANK UNTIL THE NEEDLE STOPS CLIMBING. MAKE A NOTE OF EACH. NEXT, ADD OIL TO EACH CYLINDER USING AN OLD PUMP STYLE OIL CAN. ONLY A FEW (2-3) PUMPS. IF YOU DON'T HAVE ACCESS TO A PUMP DO YOUR BEST TO PUT A COUPLE OF TABLE SPOONS OF OIL IN EACH CYLINDER. THIS WILL CAUSE THE OIL TO FILL THE GAP IN THE RINGS AND GIVE YOU A BETTER COMP. READING THIS NEXT TIME. ALSO, THIS TEST WILL SHOW IF THE LOSS IN COMP. IS DUE TO BAD RINGS OR NOT. YOUR CYLINDERS NEED AT LEAST 93 PSI TO FIRE, AS LONG AS THE PLUGS ARE NOT FOULED WITH FUEL OR OIL. IF THE COMP. READING DOESN'T CHANGE DRAMATICLY LIKE 10-20 PSI OR MORE THE PROBLEM IS NOT THE RINGS.
    HOWEVER WITH 185K ON IT, THE RINGS ARE CLOSE TO SHOT AND OVERHEATING IT DIDN'T HELP IN ANYWAY. YOU MENTIONED CARBON ON THE PLUGS I SUSPECT BURNED RINGS, HEAD GASKET BLOWN BETWEEN CYLINDERS AND VALVE GUIDES. HEAT IS A KILLER!
    IN OTHER WORDS NO QUICK FIX.
    AS LONG AS THE MAIN BEARINGS HAVE NOT STACKED/SPUN AND NO CRACKS, I'D SAY ITS A GOOD SOLID CANDIDATE FOR A REBUILD.
    AGAIN I'M SORRY TO HEAR ABOUT YOUR SICK MOUSE.

    GOOD THINGS,

    BRANT.
     
  7. 74X4Burb

    74X4Burb Member

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    Thanks,I figured that engine was shot any way.so next question cheaper to buy a new one or rebuild,I have never rebuilt an engine but i gotta start somewere. I know someone that will help rebuild it, i would like to get at least 300hp.thanks.Karl

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    Last edited: Mar 16, 2011
  8. 72cheyenne

    72cheyenne Guest

    HELLO KARL,

    300 HORSES IS FAIRLY REASONABLE AND EASY TO OBTAIN. AS FAR RELIABILITY, IT DEPENDS ON HOW THE MOTOR IS BUILT.
    TAKE A CRATE ENGINE FOR INSTANCE. GM SELLS A 260HP 350 FOR ABOLUT $1200.00 OR SO. I'VE INSTALLED SEVERAL OF THESE FOR CUSTOMERS AND THEY RUN WELL, BUT NOT QUITE THE 300HP THAT YOU SEEK. YOU COULD MODIFY IT WITH A BIGGER CAMSHAFT AND A GOOD IGNITION SYSTEM AND MAKE THE 300HP BUT, YOU WOULD THEN BE FORFIETING YOU WARRANTY.
    THERE ARE MANY DIFFERENT REBUILDERS THAT DO A GOOD JOB ALSO.
    EITHER WAY YOU ARE LOOKING AT SPENDING $700-1500 FOR A DECENT ONE.
    THE SATISFACTION AND THE EXPERIENCE OF DOING YOU OWN IS PRICELESS.
    LIKE YOU SAID, YOU GOTTA START SOME WHERE. WITH HELP FORM A FRIEND, EVEN BETTER AND LABOR IS CHEAPER TOO.
    YOUR STOCK 350 WAS CLOSE TO 250HP AND IF YOU RETURNED IT TO STOCK SPECS THAT'S THE MINIMUM YOU WOULD HAVE.
    BIGGER IS NOT ALWAYS BETTER. BUILD A GOOD COMBINATION THAT WORKS WELL TOGETHER AND YOU WILL ENJOY IT FOR A LONG TIME.
    RAISE THE COMPRESSION SLIGHTLY.
    ADD A SLIGHTLY BIGGER CAM THAN STOCK.
    HAVE THE HEADS DONE OR USE VORTEC HEADS AND INTAKE TO MATCH.
    600-650 CFM CARB.
    HEI IGNITION
    HEADERS
    AND A GOOD TUNE TO GET IT ALL DIALED IN AND THERES AND EASY 300-325HP.
    JUST ENJOY AND PAY CLOSE ATTENTION.
    REMEMBER TORQUE SPECS ARE THERE FOR A REASON.
    IF YOU REBUILD YOURS, YOU CAN DO WHATEVER YOU WISH BUT, YOU ARE THE WARRANTY.
    HOPE THIS HELPS SOME KARL.

    GOOD THINGS,

    BRANT
     
  9. 74X4Burb

    74X4Burb Member

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    Thanks Brant, you have been a lot of help.I'll keep y'all posted on what I do with this truck,I am thinkin about buyin a '77 stepside so this truck might get the back burner for awhile.Thanks again!.Karl

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    Last edited: Mar 16, 2011
  10. cowboy

    cowboy Member

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    if you go to northerauotparts.com you can get a stock rebuild kit for about 170$ or so thats everything but crank and the connecting rods. they will over size the pistions and bearings for nothin'. so i would check that out. I rebuilt my 283 for like 600-700. it runs good but i needs better headers and i have a chance to get a set of camel hump heads for 100$ they have 2.02 intake and 1.60 exhaust ported and polished. they just need valve guides and a couple of stanles steel vavles to complete . thats just what i thought i would throw in there .
    Cowboy
    1961 chevy 1/2 ton shortbed step
    1962 chevy 3/4 ton flat bed 4x4
     
  11. 74X4Burb

    74X4Burb Member

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    [updated:LAST EDITED ON Sep-21-04 AT 03:24 PM (CST)]Thanks.I've gone to northernautoparts.com afew times and orderded there catalog, they look like a good source for rebuild kits I just hope this thing dosent need a ton of machine work.Karl

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    Last edited: Mar 16, 2011
  12. 72cheyenne

    72cheyenne Guest

    HELLO AGAIN KARL,

    I USE A COMPANY CALLED POWERHOUSE.
    THIER WEB ADDRESS IS enginekits.com AND THEY HAVE GREAT DEALS ON EVERY THING YOU NEED TO DO A REBUILD.
    GIVE THEM A LOOK OVER.

    GOOD THINGS,

    BRANT
     
  13. 74X4Burb

    74X4Burb Member

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    [updated:LAST EDITED ON Sep-22-04 AT 06:42 PM (CST)]thanks.I'll look into it.Say while I'am at it what special machine work has to be done to build a 383 stroker?.Karl

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    Last edited: Mar 16, 2011
  14. bowtie6872

    bowtie6872 Guest

    born on a mountain,raised in a cave truckin and....
    is all I crave
    hello
    g.m. crate part # 12486041 is 2095.95
    330hp 380 ft/lb
    9 to 1 comp..
    4 bolt mainss
     
  15. 72cheyenne

    72cheyenne Guest

    HELLO KARL,

    PARTS LIST FOR 383 SHORT BLOCK ASSYMBLY;
    1.350 BLOCK AND RODS
    A.SOME BLOCKS WILL HAVE TO HAVE THE PAN RAILS CLEARANCED IN ORDER TO CLEAR THE CONNECTING RODS ON THE LONGER STROKE CRANK
    2.400 CRANK(3.75 STROKE)
    A.MACHINE MAIN BEARING JOURNALS TO 350 SPECS.
    3.CUSTOM PISTONS FOR THE 383
    A. CUSTOM PIN LOCATION FOR USE WITH THE LONGER/BETTER 5.7 LENGTH CONNECTING RODS FROM THE 350
    4.BALANCER AND FLEXPLATE/FLYWHEEL FOR THE 400(EXTERNALY BALANCED)
    5.GASKET SET, ETC....
    THE LIST ABOVE USES THE LONGER RODS AND CUSTOM PISTONS, WHICH ARE READILY AVAILIBLE AND INEXSPENSIVE. THE TORQUE BAND IS SLIGHTLY HIGHER THAN THAT OF A 400 BUT DEFINITLY LOTS MORE THAN A 350.
    ALSO, YOU COULD HAVE THE ROTATING ASSYMBLY BALANCED AND THEN USE THE BALANCER AND FLEXPLATE/FLYWHEEL FROM THE 350. I HIGHLY RECOMEND THIS ROUTE SPEND THE LITTLE EXTRA NOW AND ENJOY FOR A LONG TIME LATER.

    HOWEVER, YOU COULD USE THE CONNECTING RODS FROM THE 400(5.565 LENGTH), WHICH ARE SHORTER AND CAUSE EXCESSIVE SIDE LOAD ON THE PISTON AND LIMITS LONGEVITY AND RPMS. BUT, THEY WILL ALLOW THE USE OF STOCK 350 TYPE PISTONS. I DON'T RECOMEND THIS ROUTE, UNLESS IT IS FOR A TRUCK THAT NEEDS THE TORQUE AT LOW RPM AND WILL NEVER SEE OVER 4500 RPMS.

    GOOD THINGS,

    BRANT
     

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