Sniper for Spread Bore manifolds.
 

Looks like Holley released a Sniper as a direct replacement for QJet owners.

https://www.holley.com/products/fuel.../parts/550-869

They claim it fits standard spread bore manifolds and fits most stock qjet air cleaners.

This may be the ticket for the 2nd gen guys that want to retain their shaker without modifying their intake manifolds or messing with drop base elements.

Since buying my first '67 GTO in 2003 I have been one of those who said he'd never switch to the dark side and give up his Quadrajet for EFI. This new one from Holley is tempting me. What really got me was the video showing the secondaries waiting until near WOT to open. The plumbing looks kind of screwy - inlets in the back, outlets in the front, but I'm seriously considering it since the one I have at the paint shop right now will end up being a pro-touring resto-mod.

What are you guys doing that have EEC and a gas tank that vents through a charcoal canister?

Maybe I'm just not seeing it, but it appears these throttle body fuel injection units everyone is so hip on don't appear to have enough vacuum connections to run a system like that properly. Especially when you have a Q-jet with the large 3/8 hose vent on the top. That would be a deal breaker for me.

My Wife's 71 Chevelle had an EEC system on it. That said, nothing was hooked up. The EEC vent lines are all on the car, but no vacuum canister. We went with a standard Tanks Inc system and vented it like a non EEC car. left the lines in tact since they are secure in case we want to ever try to run that.

I can only speak to the FiTech systems as that's what I use, but those have two large 3/8" ports, a 1/16" ported vacuum port and a 1/16" manifold vacuum port.

Since I've never seen one fully equipped, I'm unsure what kind of routing is necessary, but it would seem to me you could tie into the PCV system using one of the 3/8" ports.

Interesting. I have 2 cars with functioning EEC that works very well. One is my stock Firebird, the other has a fairly modified 454 in my chevelle that I went out of my way to keep OEM style metering blocks on with the necessary ports to run the EEC, while using an aftermarket main body on a 950 holley.

A customers car I'm doing right now, which is also a Firebird, has EEC. I just modified the Tanks Inc tank to accept the EEC lines, because our plan is to keep the EEC functioning.

I thought possibly in the future I'd try one of these units on one of my cars that will have a Tanks Inc setup, but prefer to keep the EEC functioning. Just curious if they have enough ports to do it. I'm thinking some of them just might.

Any possibility you can send me kind of a schematic on how the EEC in your chevelle is laid out and functions? I'd love to actually get it working in my wife's chevelle. It certainly would cut down on the fuel fumes in the garage.

The Tanks Inc tank has a vent in the tank itself and a vent specific to the fuel pump hat. I believe those can simply by plumbed into the EEC lines to the charcoal canister. My wife's tank has 4 total ports on it. The sender/feed, two 3/8" ports on either side and another in the center of the tank that I believe is fuel return. Does that sound correct?

I'd be interested in guinea pigging this to see if it works.

Shoot me a pm with your email and I'll send pictures on how the chevelle is setup, and also how I modified the Tanks Inc tank on the car I'm working on.
I basically soldered in 3 extra nipples in the stock locations on the Tanks Inc tank so the EEC lines on the Firebird would hook right up like factory, then capped the vent that Tanks Inc incorporates into the fuel hat, but it's there to use just in case.

Just curious- if you have multiple return lines that work by vacuum suction from the tank, won't the tank just 'suck' on the one with the least restriction?

Someone asked a similar question about plumbing the cannister and fuel return lines into a tee. I think that any fuel in the line would prevent any vapors from being returned, and unless a one-way valve is installed, any restriction between the Tee and the tank could cause fuel to flow into the charcoal cannister under pressure, and even the one-way valve might be enough to prevent any vapor from leaving the cannister. If you want to keep the cannister functioning, one of the systems that doesn't need a return to the fuel tank might be one way to go?????

One line for fuel return under pressure to the tank, with another one from the cannister seems okay. Multiple vacuum fed return lines seems like a problem.lines

I think could accomplish that by running the Corvette style system where you have the fuel filter/regulator at the back near the tank, then run the return line off the filter/regulator back to the pump. You plug the vent line attached to the fuel hat, and run the tank specific vent line to the charcoal canister.

I don't know if the Sniper systems can function in that setup, but the FiTech system's can.

The Sniper spreadbore has 3/8" manifold ports on the front and back, two 3/16" manifold vacuum ports on the front, and one 3/16" ported vacuum on the front.

Just checked it out. Only supports 500 hp?

That should be enough to run the EEC based off what I'm looking at on my cars.

Yeah I saw that. Kind of limits it's uses for some of us. Over 500hp in a well thought out 455 build these days isn't hard to do. But could be well suited for some very mild 400 HP builds and make for a nice driver setup.

It looks like they turned the throttle body sideways for the spreadbore when compared to the square bore set up.

I am so glad I don’t live in a state with emissions requirements

Neither do I up here in Yavapai County, but I still want my EEC working. That's how the tank vents, and does so in a way that isn't smelly.

Kind of a nice system actually, and is widely misunderstood. It doesn't take HP to run it, is largely hidden from view, and requires no routine maintenance, has no moving parts, and in my experience will last the lifetime of the car.

Yet so many people unhook them thinking they are doing the car a favor only to create a venting issue that causes surging and other weird problems until they realize the tank is no longer vented, lol :shrug:

Yup, no emissions requirements for pre 76 vehicles here in Colorado. I just want the EEC hooked up to keep the car as fresh smelling as possible.

So I'm getting a little obsessed with this system, to the point of visualizing the feed and return lines in my engine compartment. What do you guys think about this: the manual shows 3/8" ID hose with fittings sliding into the hose for the return line. My '67 sending unit has a 5/16" return port that I'm currently not using. Or is it 1/4"? I'm thinking a 5/16" hard line return would be okay if the sending unit return fitting is 5/16". Changing it to 3/8" would be doable but somewhat of a pain.

This would depend somewhat on the fuel pump you end up using. It would need to be appropriately sized so that a decent volume of fuel it's providing is being consumed, instead of returned to the tank.

If you end up using a larger pump than you need, you can end up in a situation where you need as large, or even a larger return line. Otherwise you build pressure in the return line which causes pressures to creep at the regulator as well.

My experience with FiTech on my 462 leads me to want to be pretty cautionary about the return line. I tried using the factory return line in my original tank with an in-line pump and it never worked. When the engine was cold and needed much more fuel, it was fine, but as soon as temps came up and the engine leaned out, I would start back-building pressure through the return. This caused a rich/lean surge in the system as the additional pressure would increase flow through the injectors. The system would see this rich condition and pull back on duty cycle until I'd get a lean stumble and the system would fire the injectors. This was bad enough the car couldn't even be moved, let alone driven.

If you want these systems to perform reliably, you can't cut corners. 90% of the failures you read about on the FiTech or Holley forums and groups are because somebody tried to cut a corner either for ease of install or to save a buck. I'm going to be extremely blunt here about this. If you don't have the budget or the time/patience to install one of these systems correctly, you're better off not doing it at all.

The carb is much more forgiving than these aftermarket EFI systems.

Exactly on point!

Generally, without enough return line, you may not be able to regulate the pressure down far enough, depending on the pump chosen.

Since this system requires 55-65 PSI, and is capable of supporting 500hp currently, I'd personally be looking at a Walbro 255 in tank pump. These pumps put out about 100psi. Regulate that down to 60 psi, and I figure conservatively at 12 volts supplied to the pump, because it's not always going to be 13.5 that some of these pumps use to inflate their numbers, then the pump should support something north of 500hp, close to 600hp, at 60 psi of pressure. That gives a cushion to account for friction and G-force. Any less of a pump and you start to be borderline at not meeting the power potential of the unit.

With that said, I'd most likely want, or need to run a 1/2" feed AND return line. That would be a very solid fuel delivery setup that won't cause any future headaches and if you're only making say 400hp, it gives you a cushion for future upgrades as well without having to go back and reengineer the system.
I find the fuel system upgrades generally cost about as much as the unit itself by the time it's all said and done, to do it in a way that I consider fool proof and trouble free.

I run the walbro 255 in my setup with -8AN feed and return (3/8"). 600 hp and under, there's no real need for a 1/2" line. Since you're pushing fuel, not pulling it, the same logic doesn't apply as when you're dealing with a mechanical fuel pump.

For reference, I run my pump at 95% (around 12 volts) constant. My injector duty cycle at 50 mph cruise is around 6%, it's 4.7% at idle. So I'm passing around 240lph of fuel through the EFI and feed/return lines without issue.

Saw that. That's a pretty low number as a limiting factor.

Thanks JLMounce and Formulajones for excellent points. Makes perfect sense. Not intending to cut corners, simply wanting to take advantage of a system that's already there. If I install this setup {still an if}, it'll be installed as specified by Holley. There's a reason they provide manuals and parts for this kind of stuff. Thanks again.

Yeah, basically plan on ripping your entire fuel system out and replacing it. My advise is to go straight to an aftermarket tank and in-tank pump. Those who go that route typically have the fewest, if any issues.

I've had my FiTech on my car for 3 years and about 15000 miles with my in-tank pump setup. Outside of a failed electrical connector that cost me $40.00 to replace, it's been rock solid after I ditched the inline pump and factory return line deal.

I mentioned that earlier. I'm willing to bet give it a little time and they'll have a spread bore for bigger HP applications. Might be as simple as an injector swap for a small bump in supportive HP.

Was looking at the specs. 2.00" secondaries, not 2.25". 715 cfm, not 750.

Hmm.

You could try it I guess if it's 5/16 and not 1/4. I would definitely not use the factory front-to-back return line though, too many bends and kinks. Might want to run a new 3/8 feed and use the factory kinked/bent steel supply line as the return. Install a pressure gauge at the EFI unit to make sure you have Holley's specified pressure, making sure that little return port is not causing a restriction.

After having done two of these on Pontiacs, if I were to do it over I would use a retrofit tank with internal pump, no question. My GTO starves for fuel in even mild corners under 3/8 fuel level using the factory tank with no baffle and an external pump. Holley's EFI tank has a great baffle system.

I am considering the Sniper EFI Quadrajet. Still in the research stage. Couple of concerns...
I need to be sure the drop base air cleaner and holds the scoop for a TA, will fit over the throttle body? This is a deal breaker for me!
Also Holley (and others) make a filter - regulator that mounts near the tank. This manages the fuel pressure and eliminates the need for a return line from the front of the car. So only one feed line is needed to the TB
Re a tank, like others have said, the Tanks Inc setup or the Holley tanks (I believe made by Tanks Inc) is the way to go. Pump runs cooler and will last longer, much quieter with the pump submerged in the tank, no fuel starvation on hard corners.

Yes the filter/regulator setups have been around for many years. Was used OEM by GM on Corvettes and probably others throughout the 90's and newer.

I never went that route on setups here mainly because they run anywhere from $50 to $70 here locally and it starts to be an expensive maintenance item replacing that every year.

If that doesn't bother you, or you don't mind ordering a few to keep on hand (ordering online is cheaper) then it's a great way to go. I've always preferred to keep the cars user friendly, meaning the throw away parts (consumables) available at local stores. So ordering a handful to keep on hand, and save money from the local store might be a viable option.

The only other issue with it is for those making decent HP that need bigger line eliminates the use of the OEM filter/regulator setup because they are just too small.

Thanks for your comments. You are correct the filter/regulator was used on the LS cars. I believe the Holley has a serviceable cartridge...again I'm still in the research phase.
Also would like to use the timing feature by modifying the original distributor.

The available headroom from the installed injectors on these units, does not necessitate the need for anything bigger than a 3/8" feed line. Remember, we're pushing fuel, not pulling it, so the same rules for fuel line size don't apply here.

A -6 AN hose will support in the neighborhood of 900hp in a pressurized application before it's size starts to become an issue. So if you want to run the corvette regulator/filter setup back at the tank, you'll be fine, as these systems only support 500-600 hp without upgrading the injectors.

I took the inspiration for my setup from the Corvette/LS system. I went with an efi return regulator back by the tank, and I run an inline filter and gauge before it hits the throttle body unit.

I've done the fuel command center, and the in-tank pump. Both work, but of the two, I prefer the in-tank pump. Cleaner, cooler, and less plumbing.

Follow up
 

I pulled the trigger and just finished the install. The base air cleaner DOES FIT with no issues. I used the Holley Filter/Regulator with the in tank pump (made by Tanks Inc). Was able to conceal alsot all the wires.
Getting ready to fire the motor today.

Awesome! Looking forward to your feedback on it!

I'll go ahead ask the question we are all wondering - does it make that glorious Q jet sound at WOT??? ;)

If all goes as planned, doing a road test Tomorrow afternoon. Ill let you know about the famous QJ sound! lol

500hp sounds like an awfully conservative rating.
4x 100 lb/hr injectors
@ 90% DC and .45 bsfc supports 800hp.
@ 80% DC and .5 bsfc supports 640hp.
Unless something else is the limiting factor (airflow, internal fuel feed restriction)

Not sure how many hp a Qjet supports, but the secondaries on the Sniper unit are a little smaller - 2" I believe, not 2-1/4."

I'm curious about this discussion on the return line size issues. I'm running a 3/8" feed and the 5/16" return. Seems to work ok but I am running higher than expected fuel pressure to the TB. Regulator is supposed to be set at 58.5lbs but I'm reading a steady72@idle at the TB. I asked the Holley rep about it. He said it was fine to 90lbs and I haven't noticed any problems with the way it runs. Maybe I just lucked out of maybe it would run better with the specified pressure. Hmmm, curious.

Well I did a quick road test, several miles and the system did good. I believe it takes 100 miles of driving, under different conditions for the system to "learn".
Then I made the mistake of moving to the next level by switching out the stock distributor with dual sync Holley/MSD compatible distributor, with the Sniper coil driver.
Honestly I am thinking about putting the original distributor back in. I cant get the car to run right, runs hot, inconsistent, busted a muffler.
There is very little support to set up and tune the spark curves and I haven't found the right combination. The base files that are available from Holley are worthless for my situation.
Will post my progress later!

Definitely run a few hundred miles with the stock distributor if it is known to be good. EFI is a major mod and should be done with no other changes to muddy the waters.

Sent from my SM-G930W8 using Tapatalk

Biggest issue that causes what you’re seeing is the distributor and computer not being properly synced up. The computer has to assume the distributor is doing what it’s being told.

So what happens if you’re commanding 34 degrees of timing but the dizzy is only providing 20?

First thing to do is get your timing light out and verify that your timing light and commanded timing advance is matched. If it’s not you’ll need to figure out why.

Commonly it could be a slipped crank pulley, distributor not locked out or off a tooth etc.