Help please 300 to 350

Discussion in 'Small Block Tech' started by Rob Grier, Feb 28, 2019.

  1. Rob Grier

    Rob Grier Member

    Hello, I have a 1967 skylark 300 CI engine that is shot, , cam snapped and rod went thru the side of block/oil pan. I have it out at a local shop, having a hard time finding a replacement I would like to replace with the 350 because, or bigger if trans matches up . I think it would be easier down the road to get parts. What can I use as a rebuild to replace with out doing any mods or transmission changes. Really appreciate any constructive feed back. Thank you, Rob.
  2. 455monte

    455monte Well-Known Member

    350 engine should bolt up to your existing trans .
    I believe mounts are same or similar and accessories should bolt on also
    Rob Grier likes this.
  3. 455monte

    455monte Well-Known Member

    Assuming u mean a 350 buick.
    A 350 chevy will require a ton of different brackets and trans or a trans adapter
    Rob Grier likes this.
  4. patwhac

    patwhac Well-Known Member

    Is there any way you can post a pic of the snapped cam? That would be insane to see, I've never heard of catastrophic camshaft failure!

    And to echo what others have said, a 350 Buick (not Chevy) should be a direct bolt in affair. Easiest way to tell the engines apart is by the distributor location, Buick engine will be in front like your 300, Chevy will be in the rear. Also valve cover bolts; SBC had 4 per side and SBB has 6 per side!
    Rob Grier likes this.
  5. Rob Grier

    Rob Grier Member

    Thank you, any ideas on where to get a engine, buick.
  6. Rob Grier

    Rob Grier Member

    yes I will get pics tomorrow, thank you for the input.
  7. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    You could post an ad here in the parts wanted section, looking for a sbb 350.

    Plus if you upgraded your profile with your location, someone local to you reading this thread may be able to offer you one?
    Rob Grier likes this.
  8. philbquick

    philbquick Founders Club Member

    Like others have said, it should bolt-up. I'm sure the header pipes will need to be replace. If it helps, I have a good rebuildable (minor) 300 ($300)and a carborated turbo V6 ($500) that will also bolt to the same trans and mounts.
    Rob Grier likes this.
  9. 455monte

    455monte Well-Known Member

    I have a running 350 buick 2 barrel motor.
    Its in a parts car and i would sell the motor.
    No idea of milage or maintenance but it would be a good candidate for a mild build.
    Where are u located?
    Rob Grier likes this.
  10. Mark Demko

    Mark Demko Well-Known Member

    Im sure the rod broke the cam.
    philbquick, Rob Grier and pbr400 like this.
  11. pbr400

    pbr400 68GS400

    I had a ‘68 Wildcat years ago that had thrown a rod, windowed the block, broke the cam into three pieces, and spit about a fourth of it out the back of the block between the block and flexplate. It would still run!
    Yeah, post location, buy a Buick 350, either seek or convert to four barrel, tune it, time it, enjoy it.

    PS. I bet your pick up screen got clogged with nylon chunks from the original timing set and starved it of oil. Did it start with noisy valve train? Pretty car, by the way.
    Rob Grier likes this.
  12. patwhac

    patwhac Well-Known Member

    Holy crap! :eek:

    I didn't really understand what "nylon coated" timing gears meant until last weekend. I was going through a bag of random parts someone had throne in with a set of heads and came across an original timing set that had half of the nylon missing from the upper gear teeth! I could easily peel away the rest of the nylon! How did they ever think this was a good idea??
    Rob Grier likes this.
  13. Mark Demko

    Mark Demko Well-Known Member

    Most people think that, its actually very durable, but they do have a service life.
    How about running a cam with a cogged rubber belt, a lot of manufacturers say replace at 60,000 miles:eek:
    philbquick, pbr400 and Rob Grier like this.
  14. Rob Grier

    Rob Grier Member

    I agree the 350 seems to be the best idea, thank.
  15. alec296

    alec296 i need another buick

    Engine mounts should be good for 350 drop in.
    I would go 350 trans too over the st300 trans. Another basically direct swap
    Rob Grier likes this.
  16. Jim Blackwood

    Jim Blackwood Well-Known Member

    2004r tranny would be a good upgrade.

    Rob Grier likes this.
  17. patwhac

    patwhac Well-Known Member

    Haha good point!

    To the OP here's a good thread about the 2004R swap if you want to go that route. I have one from an 85 GN sitting in my garage waiting to go into my Skylark some day.

    Another good member to ask about the 2004R is TexasT, he rebuilt his own!
  18. Grandpas67

    Grandpas67 Well-Known Member

    Years ago I did the 300 to 350 swap in my 67 Skylark. The 2 speed bolts up without issue. the only issue I had was figuring out the motor mounts (I think we went with the stock 300 mounts). Also, the switch pitch plunger that hooks to the carb was never put back on due to no mounting holes on the 350. You would need to make a custom bracket to make it work. Eventually I swapped it over to a TH350 so the switch pitch isn't an issue now. However, hooking up the kickdown cable is the next thing that will need a custom bracket (still haven't made one yet and you can get away without it (I shift manually if need be)). Also, you'll have to figure out exhaust after that. You can take it to a muffler shop and they can make a new y pipe to fit into the stock exhaust...or you can go after market duals now...your choice.

    You guys were talking about the nylon teeth on the cam gear. Here's what I found when I opened up my GS400 motor...some missing nylon.
    Rob Grier likes this.
  19. alec296

    alec296 i need another buick

    Spectre cable bracket

    Attached Files:

  20. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    No need for a kick down cable if you swap in a manual valve body in that TH350 because you'll have to shift manually.

    Even more funner if your sbb 350 can spin more than 5,000 RPM!;)
    Rob Grier likes this.

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