Lessons Learned (Read This First)
• EFI will expose old-car issues. Most of my early problems weren’t “Sniper problems” they were warm-up, thermostat, and adjustment issues common to 50+ year-old cars.
• Use a 180° thermostat. A 160° stat (especially with a heavy-duty fan clutch) made it hard for the ECU to settle and learn properly.
• Set the IAC correctly. The engine must be fully warm, and IAC needs to land between 2–10%. This is done with the curb idle screw, not software.
• Mock up the O₂ sensor before drilling. I ended up with only ~1/4” clearance to the transmission pan, measure twice.
• Throttle linkage takes creativity on Mopars. There are no plug-and-play solutions like GM/Ford that I know of. Expect to fabricate or adapt.
• Let the car warm up before judging it. Idle will be high and a little erratic when cold. This is normal.
• Drive it. Short cruises helped the Sniper settle far more than driveway tinkering.
• Stock look is totally achievable. Factory air cleaner fits, hood closes, and nothing screams “modern” under the hood.
I know there are already several threads on EFI, but I figured I’d document my own experience installing a Sniper 2 on my ’67 Barracuda, in case it helps someone on the fence.
I like to keep things old school, but I also value reliability since I actually drive the car. The setup is pretty close to stock: a 340 with a 727. Prior to the EFI swap, I replaced the Mopar distributor with an MSD 8388 Pro-Billet.
I chose the Sniper 2 mainly for simplicity, and because I wanted to run returnless fuel. I was able to do that using the Holley 12-319 in-tank pump, which is made specifically for A-bodies. One nice bonus is that it supplies a constant 58 psi, so no regulator is needed (confirmed by Holley). The pump install itself was very easy. I was able to remove the original sender without dropping the tank, and the sender wrench made it painless.
For wiring, I pre-wired the pump power to the Sniper (blue wire) using heat-shrink crimp connectors so I wouldn’t have to make connections under the car. In hindsight, I still had to connect the sender signal and ground at the rear, and the Sniper’s blue wire probably would have reached the back anyway. Posting this mainly so others can learn from my mistakes.
Fuel Line Routing
From the tank, I ran 3/8” EFI hose along the inside frame rail to just under the passenger seat, where I mounted the fuel filter. 5/8” Adel clamps worked perfectly. From there, I had to dip under the frame rail near the jack point. I didn’t want to drill the frame. I’m not thrilled with that routing, but realistically it’s the only option and the most vulnerable point it could ever see.
From there it was easy to run the line up the passenger-side firewall, away from the exhaust manifolds, and into the Sniper.
For the filter, I used a 30-micron Evil Energy filter with clamp from Amazon. Make sure you use EFI-rated hose barbs and clamps. Also note: you’ll need a 6AN barb fitting to connect the fuel line, and if you’re running returnless you’ll need a plug. Holley does not include one.
Fuel Pump Block-Off
Next was removing the mechanical fuel pump and installing the block-off plate. This earned me a few bloody knuckles, but a rubber mallet eventually convinced it to cooperate. I used RTV on the seal plate.
Coolant Temp Sensor (Learn from My Regret)
I installed the coolant temperature sender in the driver-side block port and drained the coolant first. This turned out to be a mistake.
I had already bought a thermostat spacer with extra ports from Mancini, but for some reason wanted to use the block port for a cleaner look. The Sniper temp sensor wires are not long enough, so I had to splice the 20-ga wires...not fun. On top of that, my block was 1/4” NPT, while the sender is 3/8” NPT, so I had to order an adapter.
In hindsight, I highly recommend using the thermostat spacer. It avoids wire splicing entirely, and the Sniper sensor wires are shielded with foil, which makes them a pain to prep and clean.
O₂ Sensor Bung (Measure Twice…)
Another mistake: drilling the O₂ sensor hole about 1/4” too far rearward, leaving only about 1/4” clearance between the sensor and the transmission pan. I have new transmission mounts and don’t race the car, but I would’ve liked more clearance.
Mock up the sensor before drilling.
I drilled a pilot hole with a 1/8” bit, then used a step bit with a 90-degree adapter to reach the required 3/4” hole for the clamp-on bung. Take your time and use cutting fluid (Tap Magic worked great). Once past the first few steps, it went smoothly. Bung install is straightforward. I ran the O₂ sensor wire up the passenger firewall into the Sniper.
Sniper Installation
Removing the carb and installing the Sniper was easy. There’s a rear port for the brake booster, and vacuum hookups were straightforward. Fuel line connections with the 6AN fittings were painless.
Throttle Linkage (The Biggest Headache)
This was probably my biggest frustration.
I run the factory throttle cable with a clevis. I had previously ditched the Mopar kickdown setup and installed a Lokar cable and bracket. The throttle cable alignment was way off.
There are adapters available for GM and Ford applications, but Mopar guys are mostly on their own. Since the cable uses a clevis, I got creative and used a 1.5” #4 socket-head cap screw as an extension. The unthreaded portion worked perfectly for the clevis. I secured it with nuts on both sides and a nylon lock nut—very solid.
Also worth noting: the correct holes in the Sniper throttle arm are not threaded. A #4 bolt will “self-tap,” but I still used nuts because I don’t think that’s what Holley intended.
Once aligned, the Lokar cable geometry was spot-on for throttle and kickdown. I did have to rotate the factory vacuum manifold slightly so the Lokar bracket and set screw would seat properly.
Once running, throttle response was immediate and downshifts were perfect.
Wiring & Power
For ignition power, I tied into the original Mopar ignition wiring. Remember:
• Brown wire = hot during crank
• Blue wire = hot with key on
To give the Sniper power during both crank and run, I installed a diode on the brown wire and used Easy-Taps to tie brown into blue, then fed the Sniper from the blue wire. Final connection was to coil negative.
For main power, I used multi-port battery terminals since the Sniper prefers clean power. Red and black straight to the battery with 3/8” heat-shrink ring terminals, mounted the relay, and done.
First Start & Learning Curve
When you first turn the key, let the fuel pump prime. I cycled the key twice before starting. Setup on the handheld is straightforward: cubic inches, cam selection, idle speed.
The car started immediately.
One thing Holley downplays a bit is warm-up. The engine needs to reach temp before idle stabilizes. I made the mistake of keeping my 160° thermostat (Texas car, heavy-duty fan clutch, cold day). The engine struggled to get above 160°, and idle was erratic.
Switching to a 180° thermostat made a huge difference.
Another key adjustment is IAC position, which needs to be between 2–10% at operating temperature. This is done by adjusting the curb idle screw (counter-clockwise). Once dialed in, everything smoothed out.
Final Thoughts
After all this, the car runs as smooth as it ever has since I've owned it. I couldn’t be happier.
I’m in my late 40s and appreciate old-school cars. I’m an A-body guy because my dad had a couple of Gen-2 Barracudas himself. He wasn’t thrilled about ditching the carb but after seeing how easily it starts and how smooth it runs, even he admitted it was the right call.
Everyone here has their own opinions, but if you’re leaning toward EFI, I’m extremely happy with the decision. It maintains a stock appearance, the factory air cleaner fits, and the hood closes like it should.
Final tip: buy some wire loom. Without it, the engine bay can turn into a wiring mess fast.
I’ll post all the photos I took and hope this helps anyone considering EFI on their A-body.
• EFI will expose old-car issues. Most of my early problems weren’t “Sniper problems” they were warm-up, thermostat, and adjustment issues common to 50+ year-old cars.
• Use a 180° thermostat. A 160° stat (especially with a heavy-duty fan clutch) made it hard for the ECU to settle and learn properly.
• Set the IAC correctly. The engine must be fully warm, and IAC needs to land between 2–10%. This is done with the curb idle screw, not software.
• Mock up the O₂ sensor before drilling. I ended up with only ~1/4” clearance to the transmission pan, measure twice.
• Throttle linkage takes creativity on Mopars. There are no plug-and-play solutions like GM/Ford that I know of. Expect to fabricate or adapt.
• Let the car warm up before judging it. Idle will be high and a little erratic when cold. This is normal.
• Drive it. Short cruises helped the Sniper settle far more than driveway tinkering.
• Stock look is totally achievable. Factory air cleaner fits, hood closes, and nothing screams “modern” under the hood.
I know there are already several threads on EFI, but I figured I’d document my own experience installing a Sniper 2 on my ’67 Barracuda, in case it helps someone on the fence.
I like to keep things old school, but I also value reliability since I actually drive the car. The setup is pretty close to stock: a 340 with a 727. Prior to the EFI swap, I replaced the Mopar distributor with an MSD 8388 Pro-Billet.
I chose the Sniper 2 mainly for simplicity, and because I wanted to run returnless fuel. I was able to do that using the Holley 12-319 in-tank pump, which is made specifically for A-bodies. One nice bonus is that it supplies a constant 58 psi, so no regulator is needed (confirmed by Holley). The pump install itself was very easy. I was able to remove the original sender without dropping the tank, and the sender wrench made it painless.
For wiring, I pre-wired the pump power to the Sniper (blue wire) using heat-shrink crimp connectors so I wouldn’t have to make connections under the car. In hindsight, I still had to connect the sender signal and ground at the rear, and the Sniper’s blue wire probably would have reached the back anyway. Posting this mainly so others can learn from my mistakes.
Fuel Line Routing
From the tank, I ran 3/8” EFI hose along the inside frame rail to just under the passenger seat, where I mounted the fuel filter. 5/8” Adel clamps worked perfectly. From there, I had to dip under the frame rail near the jack point. I didn’t want to drill the frame. I’m not thrilled with that routing, but realistically it’s the only option and the most vulnerable point it could ever see.
From there it was easy to run the line up the passenger-side firewall, away from the exhaust manifolds, and into the Sniper.
For the filter, I used a 30-micron Evil Energy filter with clamp from Amazon. Make sure you use EFI-rated hose barbs and clamps. Also note: you’ll need a 6AN barb fitting to connect the fuel line, and if you’re running returnless you’ll need a plug. Holley does not include one.
Fuel Pump Block-Off
Next was removing the mechanical fuel pump and installing the block-off plate. This earned me a few bloody knuckles, but a rubber mallet eventually convinced it to cooperate. I used RTV on the seal plate.
Coolant Temp Sensor (Learn from My Regret)
I installed the coolant temperature sender in the driver-side block port and drained the coolant first. This turned out to be a mistake.
I had already bought a thermostat spacer with extra ports from Mancini, but for some reason wanted to use the block port for a cleaner look. The Sniper temp sensor wires are not long enough, so I had to splice the 20-ga wires...not fun. On top of that, my block was 1/4” NPT, while the sender is 3/8” NPT, so I had to order an adapter.
In hindsight, I highly recommend using the thermostat spacer. It avoids wire splicing entirely, and the Sniper sensor wires are shielded with foil, which makes them a pain to prep and clean.
O₂ Sensor Bung (Measure Twice…)
Another mistake: drilling the O₂ sensor hole about 1/4” too far rearward, leaving only about 1/4” clearance between the sensor and the transmission pan. I have new transmission mounts and don’t race the car, but I would’ve liked more clearance.
Mock up the sensor before drilling.
I drilled a pilot hole with a 1/8” bit, then used a step bit with a 90-degree adapter to reach the required 3/4” hole for the clamp-on bung. Take your time and use cutting fluid (Tap Magic worked great). Once past the first few steps, it went smoothly. Bung install is straightforward. I ran the O₂ sensor wire up the passenger firewall into the Sniper.
Sniper Installation
Removing the carb and installing the Sniper was easy. There’s a rear port for the brake booster, and vacuum hookups were straightforward. Fuel line connections with the 6AN fittings were painless.
Throttle Linkage (The Biggest Headache)
This was probably my biggest frustration.
I run the factory throttle cable with a clevis. I had previously ditched the Mopar kickdown setup and installed a Lokar cable and bracket. The throttle cable alignment was way off.
There are adapters available for GM and Ford applications, but Mopar guys are mostly on their own. Since the cable uses a clevis, I got creative and used a 1.5” #4 socket-head cap screw as an extension. The unthreaded portion worked perfectly for the clevis. I secured it with nuts on both sides and a nylon lock nut—very solid.
Also worth noting: the correct holes in the Sniper throttle arm are not threaded. A #4 bolt will “self-tap,” but I still used nuts because I don’t think that’s what Holley intended.
Once aligned, the Lokar cable geometry was spot-on for throttle and kickdown. I did have to rotate the factory vacuum manifold slightly so the Lokar bracket and set screw would seat properly.
Once running, throttle response was immediate and downshifts were perfect.
Wiring & Power
For ignition power, I tied into the original Mopar ignition wiring. Remember:
• Brown wire = hot during crank
• Blue wire = hot with key on
To give the Sniper power during both crank and run, I installed a diode on the brown wire and used Easy-Taps to tie brown into blue, then fed the Sniper from the blue wire. Final connection was to coil negative.
For main power, I used multi-port battery terminals since the Sniper prefers clean power. Red and black straight to the battery with 3/8” heat-shrink ring terminals, mounted the relay, and done.
First Start & Learning Curve
When you first turn the key, let the fuel pump prime. I cycled the key twice before starting. Setup on the handheld is straightforward: cubic inches, cam selection, idle speed.
The car started immediately.
One thing Holley downplays a bit is warm-up. The engine needs to reach temp before idle stabilizes. I made the mistake of keeping my 160° thermostat (Texas car, heavy-duty fan clutch, cold day). The engine struggled to get above 160°, and idle was erratic.
Switching to a 180° thermostat made a huge difference.
Another key adjustment is IAC position, which needs to be between 2–10% at operating temperature. This is done by adjusting the curb idle screw (counter-clockwise). Once dialed in, everything smoothed out.
Final Thoughts
After all this, the car runs as smooth as it ever has since I've owned it. I couldn’t be happier.
I’m in my late 40s and appreciate old-school cars. I’m an A-body guy because my dad had a couple of Gen-2 Barracudas himself. He wasn’t thrilled about ditching the carb but after seeing how easily it starts and how smooth it runs, even he admitted it was the right call.
Everyone here has their own opinions, but if you’re leaning toward EFI, I’m extremely happy with the decision. It maintains a stock appearance, the factory air cleaner fits, and the hood closes like it should.
Final tip: buy some wire loom. Without it, the engine bay can turn into a wiring mess fast.
I’ll post all the photos I took and hope this helps anyone considering EFI on their A-body.
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