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tech. question about my 1989 TBI 350... roller or flat hyrdaulic?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by muddysub, Aug 28, 2004.

  1. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    ok i need to know if my 1989 TBI 350 has a roller cam or a flat teppet hydraulic cam in it. please help me!!
     
  2. boz42

    boz42 1/2 ton status GMOTM Winner

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    my 88 has a flat tappet, i am under the impression that all the tbi's were flat tappet, but that is just hear say, cause i don't know for sure. sorry can't be more help
     
  3. Hossbaby50

    Hossbaby50 3/4 ton status

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    I don't think trucks got roller cams till the Vortech was installed in 96. I may be wrong, but that is what is coming to my mind.

    Cars got roller cams earlier then trucks did I think.

    Harley
     
  4. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    thanks guys thats what the chevy dealership just said too.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    They are right. 1996 for roller cams in truck engines.

    Pretty easy conversion on an earlier truck block, just have to do a bit of tapping and get parts from a roller cam car engine apparently.
     
  6. sled_dog

    sled_dog 1 ton status

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    can be some machine work I think, just what I've heard. I picked up a motor out of a car for my BUrb to replace the flat tappet motor.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    *SHOULDN'T* be anything that requires machine work per say.

    As far as I know, if the block is post '86(?) then it will have the bosses for the lifter hold down. They might not be drilled, or they might be drilled but not tapped. Either way it should be a fairly simple process.

    I don't know how they handled the cam though...if there is a retainer at the front of the block, I've never seen that addressed.

    I'd like to see one of the non-roller roller era blocks to see how easy it would be. (does that make sense? heh)
     
  8. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Most blocks have the bosses for the spider tray but aren't drilled and tapped as stated, however not all blocks have the tops of the lifter bores machined to accept the lifter cross bars. The front of all the blocks starting in 1987 are cast with the cam retainer boss and the bolt holes are there and drilled and tapped for the cam thrust plate, however there were two different thrust plates used and it has to do with the bolt spacing IIRC.
     
  9. Ruthven13

    Ruthven13 1/2 ton status

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    On my '91 TBI all the bosses were there, drilled, and tapped. Needless to say it now has a roller cam!I guess by the '91 model year they just gave all the blocks the same treatment during manufacturing and then sent them on their different ways!
     
  10. dodgedude99

    dodgedude99 1/2 ton status

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    so when i go to put a new motor in my '88 K5 next year, what long block can i order that i would get the roller cam??
     
  11. sled_dog

    sled_dog 1 ton status

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    my motor is out of a 1988 Chevy Caprice. Cop car actually. A 350 out of an at least 88+ Chevy Caprice would be a roller 350.
     
  12. tx_sub

    tx_sub 1/2 ton status

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    are the caprice motors four bolt mains? and could you build a stroker with a two bolt main block?
     
  13. sled_dog

    sled_dog 1 ton status

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    2 bolt, and mine is in the middle of a 383 build up /forums/images/graemlins/wink.gif. Maybe yet I will put in a splayed main cap setup.
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    From what I've seen of replacement motors, trucks were the ONLY ones to get 4 bolts later on, in the roller cam vintage.

    I didn't check on Corvette motors though. No real reason to go with a four bolt over two bolt for most people.
     
  15. tx_sub

    tx_sub 1/2 ton status

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    where do you draw the line between two and four bolt? obviously a crazy motor with high compression and nitrous needs four, but can a two bolt handle a mildly built 383. meaning good power but still a reliable 100k+ engine.

    forgot about the splayed four bolts. cool design. are the 454's two or four bolt mains. they produce more power stock. so if two works for them, why not a good small block.
     
  16. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    4 bolt mains are only needed in high HP applications or desired and suggested when supercharging or turbo charging.

    Lots of BBC are 2 bolt main engines. Also a 2 bolt block that is converted to 4 bolt is stronger than a factory 4 bolt block. When you convert using splayed 4 bolt caps it is even stronger yet. /forums/images/graemlins/thumb.gif

    Do you need a 4 bolt engine for a wheeler, NO. Would it hurt if you had a 4 bolt engine, once again NO. I say stick with whatever you already have unless you're planning a blower or turbo in the future. /forums/images/graemlins/thumb.gif
     
  17. sled_dog

    sled_dog 1 ton status

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    2 bolt really is fine. I have no worries about running the 2 bolt with the 383. Now in my wheeler I want the 4 bolt. My 355 in there has a forged crank and 4 bolt block. I want to get some forged rods, pistons, and throw osme juice at it.
     
  18. dodgedude99

    dodgedude99 1/2 ton status

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    so the caprice engine would work with all the K5 accessories and bolt up to the 700r4 no problem?
     
  19. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    so the caprice engine would work with all the K5 accessories and bolt up to the 700r4 no problem?

    [/ QUOTE ]

    Yep.
     

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