Holley Sniper EFI

Conversion from Carb to EFI.

Will add detail as I go along.

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Hope this will give you ideas and possible help.

After making decision to update to Holley Sniper EFI I started shopping and all were listed at $999.95 or higher for the basic kit. The master kit which included electric fuel pump, 20 ft hose, filters, fittings & hardware went for $1250.  I only need the basic kit as my Vette already had Rock Valley SS fuel tank with in tank fuel pump and return line. One Ebay vendor had Master kit listed as an auction not Buy-it-Now and the bid was $1025 with just a few minutes to go so I bit $1035 and won. I ended up with lots of extra stuff for $35 of which some I will use other stuff resell on Ebay.

On with the install J

Instructions are fairly good but as with all generic instruction there is lots of questions. I searched internet (not only Corvette Forum) for Sniper install and got lot of good tips and things to look out for. Read – Read the instruction a try to visualize where all the fuel lines and wiring will go. Also think how any other modifications that are going in at the same time to avoid duplicating efforts.

In my case I was also installing a 200-4R automatic overdrive transmission, Wilwood brakes, 6 Tail Lights, removing MSD ignition and cleaning up wiring. They may not seem like they are connected but indirectly they were when it came to wiring.

In my research it seem that a single plane intake manifold worked better then dual plane BUT not necessarily in all cases. I decided to go with a “461” intake (64-65 L79 Vette, Chevelle, Nova, Camaro) I had on the shelf in the basement. I know from the factory they were dual plane but mine had plenum milled way back when that was the thing to do. But before using it needed a good cleaning. While waiting for intake and working on brakes I tackle wiring. Even though the Vette was a frame off with all new wiring the additions by prior owner of Stereo (Big Amp & Blue Tooth), Dual Electric Fans and MSD ignition there were splices and taps were they should NOT have been -- mainly splicing lots of switch Items on one line(fuse). Besides Sniper requires a switch line so I added a fuse block with a fuse for each item requiring switched input. Also there were multiple relays for fans coming from factory A/C unit and more from separate sending unit in intake manifold??? At the same time I incorporated requirements for the Sniper unit which were 12+v in and ground from battery, fuel pump, fan 1 & 2, temp sensor, O2 sensor, coil input and high res touch screen display.

As mention above I already had SS fuel tank with internal fuel pump. But the return line had been disconnected and the wiring was of small gauge. Those required pulling of the gas tank which required pulling the exhaust but exhaust need pulling anyway for 200-4R install.

With the wiring done, tank reinstalled and intake on the rest of the install was fairly simple. Bolt the EFI/ECU on hook up the wiring and gas lines. Throttle linkage hooks up like stock carb. I needed new brackets to incorporate the TV cable for the 200-4R. Where to place/hide all the Sniper wiring plugs were a concern at first but ended up zip tied them all together and place them under the windshield wiper motor and with the distributor/plug wires/Air Cleaner installed you can't see them.



Click on images for larger view

As arrived
More than I need
Master Kit Includes
Classic Gold Finish
Rock Valley SS Tank
Test Look !!
Lots of wiring
Where to start
"461" intake installed
Fuel Lines/Wiring Complete
Touch Screen Tuner
in GloveBox

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