New SBC350 questions

Discussion in 'Engine Topic' started by jtherrien, Sep 30, 2016.

  1. night rider

    night rider Veteran Member

    Messages:
    6,401
    Likes Received:
    5
    Joined:
    Aug 6, 2002
    Location:
    Bremen, Ga
    Don't believe anything, anyone tells you about an engine. We all heard the phrase "pics or it didn't happen" right, well in case of engines... 'papers or it's not real' applies.

    Get a cheap auto zone actron $20 compression gauge and test. If it's over 210 psi you will need better than 93 octane. My guess though is you will come in at the 160-175 psi range. I ran a high compression iron headed 355 for years on 93 octane fuel. It had 218 psi cranking compression. I did have to have the tune spot on though, timing pulled back, cool inlet air, 2 heat range colder plugs, jetted rich, etc. It ran for around 6 years like that on 93 octane before cracking #2 cyl. piston at ring lands.
    Now I run an 11:1 355 with alum. heads on pump 93 octane fuel, but this one has a bigger cam and only makes 205 psi cranking compression.

    Nobody builds a race engine using 76cc 400 sbc smogger heads.
     
  2. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

    Messages:
    10,310
    Likes Received:
    450
    Joined:
    Nov 4, 2004
    Location:
    Ringgold, GA
    Check you local auto parts store, most have a tool loaner program, see if you can get a inspection camera. Stick it in a spark plug hole, it'll tell you if you have flat or domed pistons.
     
  3. Damon

    Damon Veteran Member

    Messages:
    12,939
    Likes Received:
    21
    Joined:
    Nov 16, 2000
    Location:
    Philly area
    You younger guys realize that when even an old man like me knows "there's an app for that" you might want to rethink what the meaning of "tools" is these days.

    For $12 you can buy a mini inspection camera you just plug in your smart phone (Micro USB, for most Android phones). I picked one of these up myself and it works good enough I haven't touched my borescope in 2 years! It's even lighted. DON'T use the Chinese-made apps that they recommend with the camera in the box. Download something better (and not riddled with spyware) from the Google Play Store.

    http://www.ebay.com/itm/like/401106090594?lpid=82&chn=ps&ul_noapp=true
     
    Kamikaze likes this.
  4. thrasher

    thrasher Veteran Member

    Messages:
    443
    Likes Received:
    20
    Joined:
    May 27, 2006
    Excellent suggestion Damon.
    Are you also on the maliburacing site? I haven't visited there in a couple of years.
     
  5. Kamikaze

    Kamikaze Veteran Member Lifetime Gold Member

    Messages:
    5,038
    Likes Received:
    6
    Joined:
    Aug 4, 2005
    Location:
    So. Lake Tahoe CA. USA
    Somthing really confused me in the parts used in this engine. A "Gen 2" intake would mean that there is not a front coolant passage and thermostat as that would be for the revised LT-1 / LT-4 engines in the mid 90's.

    While this is not dealing specifically with the original posters questions, I believe it goes to show that he may have been misled or mis understood what his friend told him. Better to follow the others advices to check the casting numbers, cranking compression, and use a scope to see the pistons before you proceed and possibly destroy your engine and your wallet!
     
  6. tom3

    tom3 Veteran Member

    Messages:
    11,945
    Likes Received:
    333
    Joined:
    Aug 1, 1999
    Location:
    ohio
    Engine should run fine on 93 Amoco/BP ultimate I'd think. Try to get cam specs, a Performer Plus cam does run a lot of initial timing advance but still should be fine with the 93 octane gas I'd think.
     
  7. jtherrien

    jtherrien Member

    Messages:
    42
    Likes Received:
    3
    Joined:
    Mar 27, 2016
    Location:
    Connecticut/Philly
    Some updates, although not much to go on. I'm getting bits and pieces slowly.
    Cam is an Edelbrock Performer, no exact specs just yet.
    I was first skeptical of this build due to the 76cc heads. I will post the casting numbers when I get home, not that it'll matter much.
    Copper head gaskets were used to "up the compression"... I assume using a smaller size to decrease total volume. Apparently (according to my research) every .010” change in thickness will net a change in volume of about 2.5cc. Again, doubt that did much.
    The intake is off of a 383. Originally the guy I bought it from said it was a "Gen II"- I never looked into it. Based on what I can see from a quick Google search, that would probably not be the case.
    Thank you for the heads up- I feel like I've been swindled. Time, inspection, and the dyno will tell soon enough....

    Apparently, the original owner was planning on punching this out to a 383 but decided to put another engine in his car instead of this one. He finished this build with forged parts and the rest is history....?

    I've ordered a little USB camera for my phone, thanks for the suggestion. I know I have a compression gauge somewhere, I'll give it a whirl when I have time this weekend and post an update. Thanks everyone for the insight, glad to know I have people around who know their stuff and have my back.
     
  8. tom3

    tom3 Veteran Member

    Messages:
    11,945
    Likes Received:
    333
    Joined:
    Aug 1, 1999
    Location:
    ohio
    Ordered and received this little camera. Spent a couple hours trying to get it to work with phone or laptop. No luck at all. I like to think I know a little about this stuff but it just won't work. Computer won't recognize camera, phone shows no connection to camera, phone app won't work, QR code goes to a defunct web site. Save your 12 bucks? I dunno. What program/driver do you you use for this?
     
  9. thrasher

    thrasher Veteran Member

    Messages:
    443
    Likes Received:
    20
    Joined:
    May 27, 2006
    What app did you try to use tom3 ?
     
  10. jtherrien

    jtherrien Member

    Messages:
    42
    Likes Received:
    3
    Joined:
    Mar 27, 2016
    Location:
    Connecticut/Philly
    Camera hasn't arrived yet but will report when it comes.

    Very briefly before the storm hit, I did have a chance to do a compression test on cylinder 8- 150psi. As far as I'm concerned, that's typical of a stock 350 am I right? Will do the rest when it stops raining.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.