Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

350 TBI to 454 swap

Discussion in 'The Garage' started by Robbie6987, Jan 30, 2004.

  1. Robbie6987

    Robbie6987 1/2 ton status

    Joined:
    Jul 16, 2002
    Posts:
    111
    Likes Received:
    0
    Location:
    killeen TX
    I have a 87 blazer with a 350 and I got a good deal on a 86 454 how hard will be to convert it to TBI i know i need the 454 TBI intake,tbi unit and computer. My question is will the 350 wiring harness,sensors and fuel pump work on the 454?
     
  2. fortcollinsram

    fortcollinsram 1/2 ton status

    Joined:
    Nov 8, 2001
    Posts:
    2,261
    Likes Received:
    0
    Location:
    Fort Collins, CO
    IN short. the answer to you question is YES. I used my existin harness in my 1987 K5 when I installed a 1992 TBI 454. I DID have to modify about 70% of the connectors since the 1991 454 TBI had a lot of differect connectors than my factory 87 350TBI, but all the correct wires were threre...I also had to add a a ground here and there (one for the EVRV vacuum solnoid) and a keyed hot 12v+ (again for the EVRV vacuum solinoid. but uther than that, all the wires that were needed for the 454 were already in use on my 350 TBI harness. Luckliy the 454 had the entire harness with it when I bout it so I just cut off the connectors I needed and added them to my existing harness. I think older 454 TBI units have the same connectors (probably 1987 through 1990 or 1991) If I were you just go to a yard and grab the TBI unit, ECM, TBI intake, and the entire wiring harness. you COULD just cut off the harness at the firewall but I would just take the extra time to get the WHOLE thing...

    The interchageability of the sensors will be dependent on the year of 454 FI you get. Like I said, my 1992 TBI had a good mix of parts that were interchangeable between the 350 and 454...but an older 454 unit may be 100% interchangable. On mine, the IAC, TPS, EGR solinoid, and MAP sensor were different between the 2 motors. The CTS, Knock sensor and O2 sensor, and the Dist connectors were all good to go...

    You fuel pump WILL work as long as it is up to snuff...My truck had a dying fuel pump but it was still doing well enough to feed the 350. As soon as I bolted the 454 in, all my old tired FP could do was allow the 454 to idle.. The AC Delco replacement pumps are the same for both 350 and 454 applications (part # EP386)

    Fuel lines were a direct bolt up, as was the starter.

    Good luck and drop me a line with any more questions...I deff. learned a lot during my 454 TBI swap and would be MORE than happy to share what I learned...

    Chris /forums/images/graemlins/peace.gif
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    [ QUOTE ]
    The CTS, Knock sensor and O2 sensor, and the Dist connectors were all good to go...

    [/ QUOTE ]

    Not sure how this was meant, but without checking part numbers, I'm willing to bet the 454 and 350 do NOT share the knock sensor. Connector is likely the same, but the knock sensor probably isn't.
     
  4. fortcollinsram

    fortcollinsram 1/2 ton status

    Joined:
    Nov 8, 2001
    Posts:
    2,261
    Likes Received:
    0
    Location:
    Fort Collins, CO
    It was on my 454 /forums/images/graemlins/wink.gif I checked EVERY part to make sure it would cross over...The ECM's are identical, save the PROM chip (#1227747 and #1228747 ECM's) as are the many of the sensors...the only diff. on my swap was the sensors at the TBI (IAC, TPS) and the MAP and the EVRV valve!
    Chris
     
  5. Robbie6987

    Robbie6987 1/2 ton status

    Joined:
    Jul 16, 2002
    Posts:
    111
    Likes Received:
    0
    Location:
    killeen TX
    Thanks for all the info ill let you know how it goes.
    Rob
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    Gotcha. Wasn't clear that the knock sensor was on the donor block.

    ESC is gonna be different too. Trucks *did* have a seperate ESC module, right?
     
  7. fortcollinsram

    fortcollinsram 1/2 ton status

    Joined:
    Nov 8, 2001
    Posts:
    2,261
    Likes Received:
    0
    Location:
    Fort Collins, CO
    Good point /forums/images/graemlins/smile.gif Yeah I had had to ground one of the ESC wires IIRC. But the plugs AT the distributor FROM the ESC were the same on both engines..

    Chris
     

Share This Page