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engine swap

Discussion in 'The Garage' started by LlanoK5, Nov 10, 2002.

  1. LlanoK5

    LlanoK5 1/2 ton status

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    Ok, here's the deal. My 305 is blowing oil all over the place. I want to swap in a 350. My question is will the acceseries from the 305 (A/C, power steering pump, etc...) fit on the 350.

    On the other hand I've got a friend that keeps trying sell me an Oldsmobile 455. My problem with that is that I don't think that it would be a direct bolt in swap. Anybody know about motor mount locations and boltability to my SM465.

    Thanks in advance for the help.
    Kirk
     
  2. Muley

    Muley 1/2 ton status

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    Someone correct me if I am wrong, but you should be able to reuse all the acceseries. The 305 and 350 are hte same block different stroke.
     
  3. ben427

    ben427 1/2 ton status

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    all the 305 accessorie will bolt straight on to your 350, they are different blocks, with the same stroke, but all the holes are in the same places, and they are the same outside.
     
  4. ben427

    ben427 1/2 ton status

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    the 455 has completely different bellhousing patterns and motor mount locations than a chevy big block. you could get adapaters
     
  5. georgiared84

    georgiared84 1/2 ton status

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    I believe the flexplate is a different one for the 350, but other than that you doun't have to change anything. I did one on a chevy c30 and we reused everything (including the vacuum) except the flexplate. It's been a while so I may be wrong.
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    </font><blockquote><font class="small">In reply to:</font><hr />
    The 305 and 350 are hte same block different stroke.

    [/ QUOTE ]

    Same stroke, different bore.

    Rene
     
  7. LlanoK5

    LlanoK5 1/2 ton status

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    Thanks for the help guys. Next question, what is the flexplate?
     
  8. mdm365

    mdm365 1/2 ton status

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    The flex plate is in between the engine and trans.The the flex plate has the ring gear for the starter to make the engine turn over and also puts the power to the trans by the converter /forums/images/graemlins/thumb.gif hope this helps!
     
  9. fortcollinsram

    fortcollinsram 1/2 ton status

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    The flexplate, or the flywheel, is the wheel mounted in the back of the engine. It has a ring gear on it that the starter drives to start the motor. a flexplate is a flywheel for an automatic tranny...the torque converter bolts to it. For a manual tranny, it is called a flywheel and the clutch disc is held against it with the clutch pressure plate...As long as the engines are the same era, and they have the same tooth count, you sould be able to interchange the 305 flywheel on the 350...If not, you can get a new flywheel pretty cheap or get a used ony for you application and have it resurfaced...

    Chris
     
  10. speedup

    speedup Registered Member

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    A friend of mine had the same problem. He spent about 6 weeks replacing the engine w/350. From what I understand, the exhaust didn't match up correctly (he tried to put headers from 305 on 350--didn't work). He had flywheel trouble, as well. The rest of the problems were due to inexperience... /forums/images/graemlins/shocked.gif
     
  11. milspecjimmy

    milspecjimmy 1/2 ton status

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    a 305 is identical in every way shape and form as far as the heads and block as a 350. headders, intakes, flex plates, cranks, timing components, rods, even cams will interchange. a 305 is a 350 with 283 pistons and a smaller cam to pit it simple. even the head bolts are the same.
    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif
     
  12. bablazer73

    bablazer73 1/2 ton status

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    although most pieces will interchange, some depend on years of engines. In 1980 GM changes the block and put dipstick on other side of engine. The exaust manifolds are different for left and right dipsticks. oil pans are different. The flexplate is the same, but while you have it out, I would check flexplate for cracks or just spend the 30 bucks for a new one. Also, some 305's had different timing marks on front cover, so they may not interchange. I think putting the old's motor in is alot of work. bellhousings are different. You can get adapters, but I don't like them. Just my opinion.
     
  13. txbluethunder

    txbluethunder 1/2 ton status

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    flexplates changed in 86 for the one piece oil seal. 85 and older have different flexplate.
     
  14. LlanoK5

    LlanoK5 1/2 ton status

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    Well, after doing some checking around. The best price I can find on premium long block won't take a 305 core for a 350, so it looks like I'm gonna have to stick with 305 /forums/images/graemlins/frown.gif. It's not a choice that I like, but since I don't have an abundant cash source it's the best I can do.

    Thanks for all the input, now I'll have a better clue when I decide to just spend everything that I have.

    Kirk
     
  15. ds350

    ds350 1/2 ton status

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    Have you checked the price from your GM dealer?? They have a basic 350 for a decent price that comes with a 3 year warranty. I would not spend any $$ on a 305, when you can get a 350 for a few dollars more. /forums/images/graemlins/k5.gif
     
  16. Z3PR

    Z3PR Banned

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    Buy a used 350 from a salvage yard befor a new 305 long block !!!!!!!!!!!!!!!!!!!!!!!!
     
  17. Larry_in_Tx

    Larry_in_Tx 1/2 ton status

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    I've got a running 305 in my garage if you're interested. Sight unseen, I'm not sure if it's worth the drive to you but it's an option. Let me know, I'll send you more details and a pic or two.
     
  18. txbluethunder

    txbluethunder 1/2 ton status

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    dude...don't touch that 305. its not worth it. go to a junk yard and pull a 350. i'll look around up here and see if i can pull some strings. it won't be great but it'll be rebuildable.
     
  19. Derf00

    Derf00 1/2 ton status

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    What's a rebuildable 350 w/4 bolt main worth? I have one I need to get rid of, 350 TBI w/intake. I live in Abilene. /forums/images/graemlins/grin.gif
     
  20. txbluethunder

    txbluethunder 1/2 ton status

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    running? 500 - 700. non running, but rebuildable, 300-500.
     

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