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350 block question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ftn96, Mar 29, 2001.

  1. ftn96

    ftn96 1/2 ton status

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    I have a 69-80 350 2 bolt main, 2 piece rear main seal, its 30 over now nad has been sitting out and is a bit rusted. Would this thing be worth messing with for something less than 400hp?
    The casting number 3970010

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  2. HarryH3

    HarryH3 1 ton status Author

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    Good 350 blocks can be had for very short money. I'd use that one as a core. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
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  3. Andreas

    Andreas 1/2 ton status

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    Sure! 010 blocks are good blocks. Something about the casting itself and what metal mixture went into them. Dunno the whole story[​IMG]. 2 bolts with ARP bolts holding the mains will have no problem with 400 hp and rust can be honed out[​IMG].

    /Andreas

    406cui of pure sh*t[​IMG]
    <A target="_blank" HREF=http://hem.passagen.se/znus/>http://hem.passagen.se/znus/</A>
     
  4. ftn96

    ftn96 1/2 ton status

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    Yeah, I was thinking the same thing HAIR-E... But I was wanting to find out a little more info like what Andreas was talking about.

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    I can see no reason to scrap a "good" block. I know you can get a .040 overbore and have no problems...You'd have to have some SERIOUS wear for it to need more than .010 to clean up the cylinders. Anything .005 and under cylinder-wear wise, you can get away with new rings and a hone. (been there, done that)

    So if you weren't the person that removed it (IE no clue what was wrong with it, if anything) take it apart, have the block magnufluxed (probably 40-50 dollars) if the block checks out, start from there! The beauty of the SBC is the availability and relatively low cost of parts.

    Still not buying into that "010" cast on the back of the block=better block bit, since I will bet that your block casting ENDS in 010. Probably even cast in where the timing chain cover covers. : )


    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  6. ftn96

    ftn96 1/2 ton status

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    Well the motor twisted a frame in a chevy 2 with hte 2.02 heads that I got with it, and then it was installed in a truck and then it spun a main bearing. The crank was shot so I scrapped it and have a supposedly good cast 350 stock crank, for free. I stripped it down myself and while the cylinder walls were rusted, I could still persuade the pistons to move with the slight help from a 2x2 adn a 5lb sledge. It wasnt tooooooo bad. But I know that I can take it 2 .060 over, but would prefer not to unless I had to. But Im taking it to a machine shop here that builds hi-pro motors and see what they say.

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    I'd stick with .040 personally...060 is considered the extreme max on a 350, (IE you may have a problem running hot due to thin cylinders) and offers VERY little benefit over an 040 bore.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  8. ftn96

    ftn96 1/2 ton status

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    Im just hoping than .010 will get rid of the rust.

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  9. Emmettology 101

    Emmettology 101 3/4 ton status

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    You may be able to get away with just a hone....

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; <A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A>

    "Pimpin aint easy!"
     
  10. Burt4x4

    Burt4x4 3/4 ton status

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    OK here is what I know about the 3970010 cast #. I have read that this cast # has the highest amount of nickle content for early 70's 350's two piece seal. I have two of thease blocks. 1 is in my rig now and the other is a bare block I picked up fer 50bucks. Both of my 3970010 blocks are 4bolt main! So from the info I have read over the years this cast # is a favorite for allot of gearheads doing 350 buildups! Plus I'm sure the early 70s pumped out allot of thease so they are everywere.....http://www.burt4x4.coloradok5.com
     
  11. ftn96

    ftn96 1/2 ton status

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    Well, Emmett, I want to go to the .040 adn I have some 74 cc 2.02 heads that I want to put on, and a stock replacement cast crank. Im hoping I can get my ratio somewhere in the mid 9's to low 10's. With the 74 cc heads I have lots of room to fill to get my compression up to those numbers. I know I can shave the heads but I dont know if they have been shaved already or not. But Im just going to take the block to the shop first, and get them to spec it out for and see if its all good. Then I'll start on building the block, then go with the head work. I will need to get a cam kit with all the head hardware to match, but I'll let the head shop figure those numbers out for me. Then I need to decide on the fuel. You all think my stock TBI will work for 300 ish HP or will I need to go ahead and drop a carb in there pumping what 650/700 cfm????

    Im looking for 300 to 350 HP after all is said and done. And this is my first rebuild so I need some direction.

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  12. Burt4x4

    Burt4x4 3/4 ton status

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    Sounds like you are gonna wish you just made a 383 stroker and went for the 350 to 400hp range?? Can you say 415+ftlbs of torque?? Ohhh Yaaa baby!! That is what i'm gonna do to my second block. Smart idea too, matching the valve train with your cam. But I am gonna stick with 194s and stay away from the deep throted 202s. I am gonna build EVERYTHING for LowEnd Torque. Idel to 5000........
    Research reaserch EVERYTHING then start droppin $$$ on parts. Good luck on this funstuff.......

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <A target="_blank" HREF=http://www.burt4x4.coloradok5.com>http://www.burt4x4.coloradok5.com</A>
     
  13. HarryH3

    HarryH3 1 ton status Author

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    Your stock TBI can't deal with 300 HP. That's a 50% gain over the stock 200 HP or so. You'll need a custom chip that knows about the engine mods and possibly either larger injectors or an adjustable fuel pressure regulator that will let you force more fuel through the stock injectors.

    <font color=black>HarryH3 - '75 K5</font color=black>
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  14. ftn96

    ftn96 1/2 ton status

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    Well, Burt I too would love to build a 383 and drop in there, but I dont want to do it with this motor. I plan on doing that with the 4 bolt that is in the truck right now. Im basically using the 2 bolt motor for learning and a temp replacement so I can start on the 383 and take my time on it and do it the way I want it. But hell I haven't made no definate decisions.

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  15. Burt4x4

    Burt4x4 3/4 ton status

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    hahah, I hear ya! I will think I want it one way then the next day I think I want it another way.....too many different directions to go..........

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <A target="_blank" HREF=http://www.burt4x4.coloradok5.com>http://www.burt4x4.coloradok5.com</A>
     
  16. Dieselmh

    Dieselmh 1/2 ton status

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    You can buy a kit to drill and tap the block to make it a 4 bolt main. I think ARP makes it, look in Summit or Jegs magazine. The outside bolts are angled, and supposedly make it stronger than a factory 4 bolt main. It may be worth looking into. Cheap insurance.

    Diesel
    [​IMG]
    Who says that size doesn't matter?
     
  17. HarryH3

    HarryH3 1 ton status Author

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    Those are called splayed bolt main caps. They're supposed to be much stronger since the outer bolts are threaded into a beefier part of the block. I don't know if I would want to try to drill and tap those holes at home though. The bolt angles need to be perfect or the bolt heads won't be square on the cap. Seems like a job for the machine shop to me.

    <font color=black>HarryH3 - '75 K5</font color=black>
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  18. dyeager535

    dyeager535 1 ton status Premium Member

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    I too have read/heard this from numerous people, old and new. The fact remains that the 3970010 block is probably the most common 350 block out there (what, 69-80 it was cast?) and that every single 3970010 block I have seen has the "010" cast into the back. Check blocks that are NOT 3970010, and more than just by a mere coincidence, on the back of the block, are the last 3 of their casting number....IMO, that is just the last 3 of the block casting number. The only thing I can't explain is the "020" that is sometimes cast into the back of the blocks..THAT I might buy as being a different alloy block. I'm not trying to anger anyone with this, but basically I can't find anyone that has factory documentation that this is the case....

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  19. Andreas

    Andreas 1/2 ton status

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    Woah! Did you say you spun a main bearing?? Then your block needs to be line bored. Line boring costs money. Some self proclaimed experts have written about line boring being a risky gamble and should not be done unless really necessary. Anyhow, after line bored the crank is now closer to the cam and the top of the cylinders. A special shorter timing chain would be needed to keep the proper chain tension.

    If I were you I´d look for a new block. It isn´t that expensive[​IMG]

    /Andreas

    406cui of pure sh*t[​IMG]
    <A target="_blank" HREF=http://hem.passagen.se/znus/>http://hem.passagen.se/znus/</A>
     
  20. ftn96

    ftn96 1/2 ton status

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    Yes the engine spun a main. The block looks good to the eye adn feel, but the crank that was in it was, ahhhemm.......ground up pretty good.
    But there are no groves in the raceways for the main bearings as far as the block is concerned.

    But to tell you the truth, I might just eat this 100 bones and go get another block and start fresh.

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     

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