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350HO/Vortec/TBI problems

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Hoover87, Jun 18, 2002.

  1. Hoover87

    Hoover87 Registered Member

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    I have a GM Crate 350HO with vortec heads, an '87 305 TBI truck, a new 454 TBI unit, and the GM vortec-to-TBI manifold. Old engine has been pulled and is sitting beside the new one.

    My questions/concerns are....

    The intake manifold does not appear to have a port for the metal power brake line. Any ideas?

    EGR has been disabled in the FastChip chip that I have to install. I have a plug for the port meant to receive exhaust gases but not for the place where the EGR valve mounts. For the time being can I mount the old EGR valve on the manifold and plug it? Anyone know where to get a block off plate for the EGR spot?

    So far it looks like everything else will tranfer over, with the exception of some possible throttle cable issues that i have been reading about.

    Is there anything else I should be ready for when connecting this stuff up?

    Thanks!
     
  2. Thunder

    Thunder 3/4 ton status

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    It looks like you are doing things right.
    I have a Fastchip on a 350 with mild mods and it works good.
    Dont think anyone makes a cover for the EGR valve port (smog laws). But you could fabricate one from a flat piece of metal and a gasket. Or just put the old EGR back on and block it off with a gasket that covers the holes.
    I have never seen the GM vortec to TBI manifold. But there must be somewhere on it you can get vacume from. You dont have to use the metal line. Change it over to rubber if you have to and get a connector that a rubber vacume hose will slide on to.
    As I said I am not familliar with that manifold. So I dont know how big the bores are on the manifold you have are. So make sure that 454 TBI will fit Ok. The bore on a 350/305 TBI intake is 1 11/16". The bore on the 454 TBI is 2". Bolt the TBI up to make sure the throttle plates dont hit on the manifold when they are opened. You may have to get it bored out or put in a spacer if they do.

    Make sure to adjust the TV cable when you are done if you have a 700R4 trans.
     
  3. Hoover87

    Hoover87 Registered Member

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    Thanks for the great info!

    I've already had the manifold bored to match the 454 TBI.

    The truck has a SM465 4-speed so the TV? cable you mentioned shouldn't be a problem.

    Any other input is greatly appreciated!

    Thanks again!
     
  4. JIM88K5

    JIM88K5 1/2 ton status

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    Holley or Edelbrock make an egr block off plate I think. If you have any kind of smog visual inspection, I'd leave the egr valve bolted up..
    Jim
     
  5. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Don't worry about the EGR, vortec heads don't have a port them. Take a look at the ports in the middle of the head, they're cast shut. Just put it back on there for looks and use the old Sgt. Schultz line...."I know nothing!" I belive vortec engines use a solid metal line off the exhaust manifold to get the gasses.

    The brake line can just hook up to the vac tree in the back(little hole behind where the throttle body goes). It just needs a constant vacuum source. You'll have to think up a creative way to plumb it in, but you're smart, you'll figure it /forums/images/icons/wink.gif .
     
  6. Hoover87

    Hoover87 Registered Member

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    Thanks again guys. This info gives me a new boost of confidence. The last swap I did was about 8 years ago in a '75 Chev truck. A little less to worry about in that old truck.

    I'm taking lots of pictures so I'll give a full report on the project when finished.

    Thanks!
     

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