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350 to 383 question.

Discussion in 'The Garage' started by WakeBoard&4X4er, Jun 15, 2004.

  1. WakeBoard&4X4er

    WakeBoard&4X4er 1/2 ton status

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    This past weekend I spun a barring some place in the lower half of my newer 350. so… I am thinking that it will need a crank kit so I am thinking about making it a 383.

    Here are my questions.
    1 Is there any kits out there that are just a bolt in 400 crank for a 350 block?
    2 do all blocks take modification to also the larger crank (cutting out for the more space needed)?
    3 would it be wise to change any other stuff due to this bottom end brake down?
    4. any balance things?
    5. ?????

    Thanks!

    Any input would help.

    brett
     
  2. jjlaughner

    jjlaughner 3/4 ton status

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    From what I understand there are several ways of getting to a 383. I never could find one that didn't require $500-1000 in block work and another $600ish in parts /forums/images/graemlins/dunno.gif
     
  3. lason

    lason 1/2 ton status

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    ALL 383 crank kits will require the block to be machined because the cranks throw is so much greater than the stock 350's. Also you will need to change out at least the pistons to a set with higher pin locations or your current pistons will meet the head at TDC. Most kits will require balancing or at least it is advised to do so. Basically the whole motor will have to come out and be broken down to do the swap if your serious about it. O yeah you will also need to change the flywheel and harmonic balancer if you plan on running external balancing. Personally I would just take your crank out and have it machined if it is a spun bearing and throw in a set of 10 under bearings and be done with it. Also change your oil pump while you got the pan off, its cheap insurance.
     
  4. HarryH3

    HarryH3 1 ton status Author

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    There are plenty of aftermarket stroker crank kits these days, so you don't have to find a crank from a 400. /forums/images/graemlins/cool.gif Check out Summit or Jeg's.

    Yes, you need to clearance the rails, where the oil pan bolts on, to clear the rod bolts as they swing past. Some stroker engines also require some notching of the bottom edge of the cylinders, to clear the rods, but I can't recall offhand if the 383 is one of them. /forums/images/graemlins/frown.gif

    Because of all the grinding required, it would be best to have the engine completely disassembled so that you can hot tank it before putting it back together. You don't want any extra metal shavings floating around in there... /forums/images/graemlins/eek.gif
     
  5. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    In addition to the other answers, sometimes the rod bolts need ground to clear some cams. /forums/images/graemlins/k5.gif
     
  6. WakeBoard&4X4er

    WakeBoard&4X4er 1/2 ton status

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    I think i will just do the 100 crank and call it good.

    I was thinking there was an Easy way to do this with out all the other work.

    Thanks all!

    brett
     
  7. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Well it is a PITA if you want it done now. Its my favorite motor, but won't be in my truck as long as I still drive it daily. /forums/images/graemlins/k5.gif
     
  8. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    I was originally going to build a 383 but after finding out what it costs I decided to just build a 400 because...

    1. It was cheaper
    2. Hardly anyone has a 406 and especially in a blazer not to mention I love saying " no, it's a built 406" when people ask "350?" assuming. /forums/images/graemlins/histerical.gif
    3. I liked the idea of having a 400+ ci SBC.
    4. 400's seem to wind up faster than 383's because they have a larger bore with obviously the same stroke but still make just as much torque.
     
  9. lason

    lason 1/2 ton status

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    [ QUOTE ]
    4. 400's seem to wind up faster than 383's because they have a larger bore with obviously the same stroke but still make just as much torque.

    [/ QUOTE ]

    Actually its the other way around, smaller bores and shorter strokes wind up faster than the larger bores and longer strokes but produce less tourqe in most cases. Hence the mighty chevy 302 that would rap out to nearly 8,000+ rpms.

    The 406 is still a good choice and I actually prefer it to the 383 due to less work, money and usually better results. Only problem is finding a 400 block which are harder to find than a 350. If I ever get to build up a wicked combo then Im probably going for 450+ c.i. small block but that will deffinetly cost some major green. Here is the lastest "big" small block that got my gears turning /forums/images/graemlins/peace.gif

    http://horsepowertv.com/show_details.aspx?iid=399
     
  10. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    [ QUOTE ]
    4. 400's seem to wind up faster than 383's because they have a larger bore with obviously the same stroke but still make just as much torque.

    [/ QUOTE ]

    Actually its the other way around, smaller bores and shorter strokes wind up faster than the larger bores and longer strokes but produce less tourqe in most cases. Hence the mighty chevy 302 that would rap out to nearly 8,000+ rpms.

    The 406 is still a good choice and I actually prefer it to the 383 due to less work, money and usually better results. Only problem is finding a 400 block which are harder to find than a 350. If I ever get to build up a wicked combo then Im probably going for 450+ c.i. small block but that will deffinetly cost some major green. Here is the lastest "big" small block that got my gears turning /forums/images/graemlins/peace.gif

    http://horsepowertv.com/show_details.aspx?iid=399

    [/ QUOTE ]Um a 400 will wind up faster because of it's larger bore vs. the stroke. I have alsways been under the assumption that it's the bore vs. the stroke that changes how fast it winds out. A 377 winds up faster than a 350 because it has a larger bore vs. the stroke. How about top fuel dragsters, their motors are 1,000+ ci and wind up like crazy. You can make a BBC turn just as many RPM's as SBC, just depends on the bore vs. stroke. This is my experience.
     

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