Hello everyone,

I am considering installing an EFI system on my 74 cutlass. I had some questions for you all.

1. Im pretty sure my cutlass already has a return line can i use its plumbing for the return line or is it pressurized like the sending line?
2. Which system would you all go with, Im leaning towards the Sniper EFI Quadrajet
3. I have heard people complain about the inline fuel pump noise, does anyone have a suggestion on in tank units? I really do not want to cut the tank.
4. If someone has done the sniper have you had problems with the O2 Sensor? this seems to be a common problem and wonder if i can spend extra money and get a better one.

@cutlassefi I see you install these often maybe you can help?

 

It’s best to run a proper size line, install a tank module or an EFI ready tank.
Sniper Qjet is fine if the smaller size is ok.
I’ve not heard of any issues with the O2’s, explain please. However if the bungs aren’t installed correctly or the wires cross hot parts then you’ll have a problem.
Hope this helps.

 

I can't find any EFI ready tanks for an olds. Apparently they aren't popular enough.
What do you mean if the smaller size is fine?
With the O2 sensors apparently people have had them go bad in a short time and start making the cars run very rich.

 

People think once the fuel map is done then they're done. not so. You need to address the correction limits and other things once it's done. Most don't do that.
In an everyday, properly installed and tuned system O2 failures are very rare.

 

They're called "Chevelle" tanks. Holley even sells one under the Sniper brand.

 

@joe_padavano I messaged them. They said they don't have any that fit

 

Holley part number 19-125 is the Cutlass/Skylark specific EFI conversion tank. It comes with a 255 liter per hour pump that will support around 500 hp.

 

That tank is for a 70-72. Go read the first post again. The OP has a 1974.

 

As far as the O2 sensor goes, I've done a lot of the Sniper units, and have yet to have an O2 related issue. Most issues revolve around air leaks upstream of the O2 sensor, ignition misfires, or improper wiring practices (not grounding directly to the battery, running EFI wiring across ignition wiring, etc). If you install the unit as the manual says, you'll be fine.

Travis

 

My bad.

I had a 1974 Grand Prix, and the tank was completely different than a Chevelle. the top of the tank was shaped differently, and the filler neck was different. I don't know if the Olds tank is the same as Chevelle for 1974 or not.

 

I considered installing Holley Sniper EFI on my 71. Here are 2 well rated fuel pumps I read about:

https://www.summitracing.com/parts/vpn-gca758-2

https://www.summitracing.com/parts/bch-61944

I also read that the Aeromotive 11540 is a good in-tank fuel pump. However, it's the same thing as a fuel pump for a 1989 Chevy Blazer with a 5.7l.

https://www.summitracing.com/parts/aei-11540

https://www.rockauto.com/en/catalog/...fuel+pump,6256

 

The 1989 pumps are TBI pumps, which operate at much lower pressure than the Sniper system (13-20 psi vs 58 psi for the Sniper). I’ve not flowed the TBI pumps at 58 psi, but I suspect that they will either bypass internally, or the flow will be extremely low. The Aeromotive 340 pumps are good pumps, I use them frequently.

Whenever doing an EFI conversion, it’s a good idea to swap to a tank that has the internal baffling suitable for in-tank pumps. Aeromotive’s Phantom line of pumps come with their own baffle system, and enable you to successfully install an in-tank pump into an unbaffled tank. But, they are more money. I try to swap tanks when I can, as most 50 year old tanks need retiring anyway.

 

Thanks for the heads up Tquillen!

 

I’m installing the Sniper Q-Jet, I installed the Holley Resto fuel pump in my tank, easy deal. I recommend a 4 post battery, but I you use ring connectors to the battery posts. Oh, the Holley pump allows to deadhead the fuel, eliminating plumbing a return line.
The main wiring bundle could be an issue, since the pump relay will be just to the left of the distributor, I’m doing a little rewire to mount the relay in the trunk. I’m using -6AN fittings from the thru frame 3/8” to the Sniper, out back I’m using a CK1500 fuel filter.
Holley pump link
https://www.holley.com/products/fuel...s/parts/12-303
Good luck, and let us know ...

 

The 73-77 cars can use a 91-96 GM B body tank. I know on the 76-77's they bolt right in. That's what I'm using with a 255 pump in the stock Caprice pickup. Just make sure when you pull the tank or wherever you get it, you get the THREE straps, not just two. It's a plastic tank and needs that 3rd strap for support.