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305 to 350 swap?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by EDGE, Oct 30, 2000.

  1. EDGE

    EDGE Registered Member

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    I've been calling around about swapping my 305 for a 350 and got alot of different answers.Some shops won't do it,some say they'll do it for 2000 and some say they'll do it but I'll need a new computer,oil pan,intake manifold and valve covers.I thought that the intake manifold,carb,oil pan and valve covers are all interchangeable as far as the 305 and 350 are concerned? Has anyone done this swap? 86k5
    305/700r4
     
  2. archer

    archer 1/2 ton status

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    I'm about to make this swap. I have an 85 with no computer, but tons of smog stuff. It will bolt right up, but I've heard the prom will have to be re-programmed to accept the new parameters, on computer equipped vehicles. I think you also have to retain some distributor parts and your intake manifold/exhaust manifolds.

    "who dares wins"
     
  3. Emmettology 101

    Emmettology 101 3/4 ton status

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    The 350 will bolt right up.

    As far as the intake, if you have a TBI the 305 unit is usually smaller than a 350 unit(at least with TPI) so that may be why they say you need a different one. If it is a carb'd engine your intake and carb should be fine.

    Also, if it is a computerized Blazer you will need a new Prom chip, but htis would be a nice time to go to a Jet chip for a 350!

    As far as the oil pan and valve covers, it depends on what year engine i coming out and what year engine is going in.

    I swapped out a 70's 305 for a 90's 350. pretty basisc swap other than the 90 350 I got did not have the provision for a mechanical fuel pump and that was a pain in my arse!!!

    ANymore questions? :)

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; http://emmett.coloradok5.com
     
  4. Cavalry

    Cavalry 1/2 ton status

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    I thought FI started in '87? The actual swap is very easy. You could run everything you curriently have without problems, you would just not be at peak performance.
     
  5. jimmyjack

    jimmyjack 1/2 ton status

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    It depends on what year you put in/take out. In 88, chevy went to a one piece rear main seal, thus an old style oil pan will not work. Also the two center bolts on the the heads, where the intake bolts down, the bolt holes go straight down versus being angled like the rest, so an old style intake won't work either. If your going to be charged 2 grand for an engine swap go visit your friendly chevy dealer for a crate motor. About 1200 bucks. You even get valve covers AND an oil pan.

    creepin' and crawlin'

    Jim
     
  6. jimmyjack

    jimmyjack 1/2 ton status

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    Oh yeah, the valve covers bolt in from the center.

    creepin' and crawlin'

    Jim
     

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