Results 1 to 6 of 6

Thread: Install thread - Holley Sniper EFI on '72 C10 pickup.

  1. #1

    Default Install thread - Holley Sniper EFI on '72 C10 pickup.

    First day video: Moving the truck into the shop.

    Old vs New:

    On the engine. Vacuum and throttle/transmission cable connected.

    3/4" hole drilled for WBO2 sensor. It's 10+ degrees above horizontal and near the collector.

    Derp. included 2.5" exhaust clamps for WBO2 sensor mounting, don't fit my 3" exhaust. I'll need to go buy some 3" clamps:

    Draining some coolant to install the new temp sensor.

    Temp sensor install location. May need to relocate it as I've read the reading back there can be too low.

    Got the fuel tank drained in to Jerry cans.
    Removed the mechanical fuel pump.
    Assembled the electric fuel pump and filters.

    Found a factory return line I intend to use. Need to get a fitting to step down from the 3/8" fuel hose to the 5/16" steel return line going into the fuel tank.

    I intend to keep the two 3/8" hoses (green & red below) next to each other, along the frame rail before running them up the firewall above the transmission, around the distributor into the EFI unit. I'd use the factory hard lines along the frame except they terminate way at the front by the radiator, not where I want to start running the 3/8" hose. The headers will be approx 3" away from the fuel line at the nearest point. I suspect this is OK for temps, but I'll look into something to wrap parts of the fuel hose with to protect it from heat as an extra step:

    Here's the fuel routing plan.

    High flow mechanical fuel pump vs electric fuel pump.

  2. #2


    Sweet C10! Keep us updated if you have any issues.

  3. #3


    I'd be interested to see if that coolant temp port works, because that's where I have put mine, but I have not fired it up yet.

  4. #4


    Just in case you didn't know, you can easily convert that HEI distributor, so that you can do timing control. VERY easy to do. I always felt like I was missing a very important part of the Sniper EFI on my BBC by not having timing control, but I didn't want to spend $450.00 on the distributor. Just about a week ago, I found out you can convert an HEI for about $20.00. Can't wait to do mine.

  5. #5


    I want the timing control distributor Holley makes. I plan to do it after I get this system up & running. I've watched the Holley timing distributor video and it's over may head. I'll likely get a shop to do the installation & setup for that part.
    For my C10 Sniper EFI install, I hope to go through the startup sequence tomorrow. I've got the fuel lines completed using the factory in cab fuel tank. Did the wiring.

    Part 2:

    Removed the mechanical pump and used the included plate to cover the hole. The original bolts were too long for the plate, so I had to find some shorter bolts. The electric fuel pump is mounted along the frame using some existing holes (lucky).

    I ordered some of these off Amazon.

    And after a bunch of looking found this 3/8" to 1/4" step down to connect to the factory return steel line into the stock tank. From the EFI unit in the engine bay, the 3/8" rubber return hose goes down the firewall, along the frame, through 2 of the rubber retainer clamps, into the 3/8" to 1/4" step down fitting, into a new 1/4" rubber hose, into the factory 1/4" steel return hose which goes into the cab and tank.

    I heat tape wrapped some of the fuel line and post pump filter just as a precaution, and it looks cool.

    Also got the 3" exhaust clamps from amazon so WBO2 sensor is installed.

    Made some wiring progress.

    This is an optional 10-pin connector. Most of the wires are for nitrous, etc., so I cut & heat shrinked most of them. I only need the brown wire remaining to send a signal to my tach.

    Started getting some things tucked away. I need to buy some black wire loom to cover those three wires at the top. I attached the fuse and relay to a screw by that A/C box thing.

    Tried to hide the wires as much as possible. This is the power from the battery, ran through the fender.

    What's left is connecting a blue wire (power) to the fuel pump, grounding the fuel pump, ensuring the WBO2 sensor cable is secure, terminating the yellow wire to the distributor tach signal, connecting the brown wire to the tach, connecting the pink wire to +12V when the ignition is on. Then put some gas in the tank, follow the startup instructions, including priming the pump and dumping gas into a can to fill the source hose with fuel. The end is in sight!

  6. #6


    Good news & bad news.
    The good: The truck is running!!! It idles super smooth and there's no unspent fuel coming out the exhaust.
    The bad: There's coolant leaking from the intake manifold where a crack has appeared, likely from me over tightened the heat temp sensor.

    Need to do:
    1) Replace/fix intake manifold where it cracked.
    2) Adjust throttle cable to provide 100% open throttle. Reads 85% position at peddle WOT.
    3) Wait 3 months for snow to melt

    Part 3 Video:

    Finished engine bay:

    Running & warming up:

    Me "What's that sound?"

    Green juice is good, right?

    Random pic of chains used to get one car and two trucks unstuck from my driveway this weekend. 305 studded winter tires, love 'em.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
About us
Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors have powered every NASCAR® Sprint® Cup team and nearly every NHRA® Pro–Stock champion for four decades. Now, Holley EFI is dominating the performance world as well as our products for GM's LS engine. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. As a single solution, or partnered with products from other Holley companies - Hooker Headers, Flowtech Headers, NOS Nitrous, Weiand, Earl's Performance Plumbing, or Diablosport - Holley products can give you the edge you need over the competition.
Join us