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TH350 to SM465 conversion/TPI swap

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by hirider34, Dec 12, 2001.

  1. hirider34

    hirider34 Registered Member

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    Looking for just a little bit of advice to fill in the blanks. I managed to pick up a 465/205 combo, with the crossmember, all linkages, pedal assembly, tilt column, bellhousing, flywheel for $200. I figure I have just about everything I need. The two questions I've got for you guys are:
    1.) What's the difference between the Auto/Manual wiring harnesses? Will I be able to modify the orginal to do everything I need for the Manual?
    2.) My plan is to swap out the 307 for a 383 i've had for a while. I was gonna run the TPI setup off an '85 vette coverted to speed density. What kind of wiring/throttle changes am I gonna have to make to work it into the '71 system. I know about custom harnesses, ECM, and electirc fuel pump. Just curious if anyone sells a stand-alone throttle kit for these.

    Why buy it if you can build it better?
    All Give Some. Some gave all. God bless the fallen Brothers in the FDNY.
     
  2. BurbinOR

    BurbinOR 3/4 ton status

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    Hirider, to to the 73-91 forum and look up the post I put up a few days ago for TPI info..........it has links to articles and other information that you will find useful.

    Other links -

    www.fuelinjection.com
    www.thirdgen.org (Camaro board with TPI specific info)



    <font color=blue>'79 ONE TON TPI K5 - See it at---&gt;<a target="_blank" href=http://www.blazzinor.rockcrawler.com>www.blazzinor.rockcrawler.com</a>
     
  3. Steve_Chin

    Steve_Chin 1/2 ton status

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    The major difference in the auto and 4-speed wiring harnesses have to do with the back-up light switch and the TCS. Those changes can pretty easily be fabricated, but you could also just get those wiring harnesses used from Vintage Chevy or as new repops from M&amp;H Electric Fabricators.

    I don't really see a need to convert an MAF system to Speed-Density (I'm building a hi-po MAF system for my Blazer), but there are a number of aftermarket kits to do the conversion with. Be aware that the early throttle body's main difference from the later ones is the idle air passage (or lack of one in the earlier throttle body). They are otherwise identical.
     
  4. hirider34

    hirider34 Registered Member

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    Steve Chin, Thanks for the info about the harness. In regards to the TPI, several sorces I had spoken with claimed the MAF systems were complicated and inefficient, and that a retrofit would be easier with the speed density system. I did not understand this since GM brought back he MAF systems in the newer F-bodies. Do you have any info. sources about your swap? THanks

    Why buy it if you can build it better?
    All Give Some. Some gave all. God bless the fallen Brothers in the FDNY.
     
  5. BobK

    BobK 1/2 ton status

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    hirider34,I did the TPI swap into my 71 Blazer Jan. of this year.I used a throttle cable from a 92 Camaro.It's a little long,but it works.I did have to modify the area on the firewall where it passes through but again it works.You can try Lokar
    http://www.imagestation.com/album/?id=4292391623

    <font color=green>BobK<font color=green>
     
  6. hirider34

    hirider34 Registered Member

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    BobK, Thanks for the info. I had looked at your setup a couple times I think as a quick reference. Didn't you get your harnesses from Jim's Performance in MD? He's only about 20 minutes from me and has been a big help.

    Why buy it if you can build it better?
    All Give Some. Some gave all. God bless the fallen Brothers in the FDNY.
     
  7. ECNiz

    ECNiz Registered Member

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    What's a TCS???? I just put a SM465 in my 72, but I didn't
    know what that extra connector was for?

    Thanks,
    Erik

    72 K5 383ci 4" lift 35" BFG M/T's pretty orange color
     
  8. Steve_Chin

    Steve_Chin 1/2 ton status

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    Those guys that are telling you that the MAF systems are inefficient just don't have an understanding of them. TPiS has been modifying and racing those MAF systems (along with Spees-Density systems) for years. They have found that the MAF systems respond favorably to Hi-Po modifications and more readily accept modifications that allow more air flow into the engine than so the Speed-Density systems (without modifying the PROM). This is because the MAF actually measures the air flow into the throttle body where the Speed-Density systems make a best guess as to how much air is moving into the engine using the throttle position sensor, air temperature sensor, and manifold air pressure sensor as references.
     

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