Holley Sniper on a 351c

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Fabrice

Fabrice

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My Car
73 Grande 351C
71 Mach 1 429CJ
As my Holley 650 double pumper decided to leak bad one more time.

I just made the jump and ordered the Holley Sniper, master kit #550-511K, as I've

seen not much Holley parts keep their shiny finish for long. I went for black ceramic.

I've ordererd a separate bung to weld it for durable installation vs the clamp thingy they provide in the kit.

As usual, no support for ford kickdown, so ordered a Lokar kickdown kit for the fmx that should fit just fine and use the

non ford provided stud on the unit.

I've red like 10 times the specs, watched a bunch of EFI installs vids. I think I can get that baby up&running

without major probs. Too late for second thoughts anyway!

However, since it will be shipped end of june (aaaaaarggggghh, means mid july over here) and as none of the videos

I've seen covers a 71-73. I have a few questions unanswered... and would like prep some stuffs if possible before it arrives.

Like, what would be the best route for the fuel lines? Best location for fuel pump? Ideal location for the sensor...? Tips?

If anyone already installed one of these please (or another carb replacement EFI) come forward and tell me all about it so I can endure this looong wait :)

 
Thx Don, I've of course found and red these threads already :))

Since the Holley is now out for a while and these threads relatively old, hence the new thread.

As fuel is more or less liquid gold over here, and most carbs far from being as efficient as EFI, I bet many did the maths like me.

Yet as it cost you an arm first before it hopefully saves you in the long run, i'd like to install it using as much as tips/experiences as possible...

 
Just did mine with an ezefi 1.0 and it was fairly straightforward.

I ran the fuel lines along where the stock one goes into the part of the fender under the brake booster; then to the throttle body on the back side of the motor. I used an external walbro 255 and mounted it in the lower part of the wheel-well near the front leaf spring mounting point. It's not really an ideal spot for it though as the hose has to go up then down to the suction side of the pump. Could potentially cause some priming issues if it gets run out of fuel. May change it up later.

The o2 bung I put in my exhaust pipe just past the header collector on the passenger side; Ideal would have been right before the header collector, but removing the exhaust pipe was way easier to do in order to get the bung welded right.

The water temp sensor I just used the stock location and put my gauges sensor into the 2nd port that was blocked in the water pump.

I moved all my ignition wiring to the drivers side of the car and ran my efi wiring along the passengers side; supposedly the noisy ignition wires can cause some issues if they are near the efi wiring. This would probably be reduced with the sniper system as there will be less wiring to do.

I also put some nice new grounding straps onto the motor. Seemed like a cheap item to do in order to limit possible electrical issues.

 
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For the 2 filters and the pump, i'm thinking about welding/making some bracket and place it behind tank. Did you reuse the return line from sender unit? For the bung/o2 sensor, Holley says it can be on both side but somehow bank 1 feels more logical. I'll do same as you did.

for the watertemp, I got an Offenhauser dual plenum manifold (dunno if they even make these anymore), fitting is same as original, so I should be ok.

For the sake of atomization, i have a spacer under my 650dp. I wonder if I really need it as injectors are supposed to do that.. Cleveland intake

temp is the only thing that makes me want keep it. Any thoughts?

I'll do similar too regarding wiring separation, except my battery is located in trunk, so I'll pass the 2 main feed of the unit thru body as I did for the positive battery cable. Where did you tap the key-on 12 volt to prim the pump that stays on during krank? Or did you use the coil positive wire?

Are you letting the system control the timing or is it as I plan first do, let it mechanical? If i'm very happy with it, I'll prolly go for the Holley distributor at some time, but for now, as the whole package was pricy enuff, I want first keep my current coil/distributor combo as its in perfect condition and see how that goes.

Most important: How does the baby feels after the install? Very curious about fuel consumption too, my 4v is so thirsty I always wonder if there is actually air mixed with it...

Must be awesome to start and get that raw idle music with no pedal pumping :)

 
I was just about to start a thread on the Holley Sniper and the 351c today then I saw yours! I just ordered the Black Holley Sniper as well off of CJ PonyParts and plan to install it on my 351c with a FMX trans. Luckily I came across your thread because I did not think about the kickdown, do you mind linking the Lokar part? I plan on using the RobbMc PowerSurge II for my application using the charcoal canister line as the return and a vented fuel cap to prevent the gas tank from being pressurized. Will be very helpful to have another person going through the Sniper install at the same time, once it arrives I plan on making a series of YouTube videos for anyone else looking to make the EFI switch in the future.  

Cheers, 

Adam

 
For the 2 filters and the pump, i'm thinking about welding/making some bracket and place it behind tank. Did you reuse the return line from sender unit? For the bung/o2 sensor, Holley says it can be on both side but somehow bank 1 feels more logical. I'll do same as you did.

for the watertemp, I got an Offenhauser dual plenum manifold (dunno if they even make these anymore), fitting is same as original, so I should be ok.

For the sake of atomization, i have a spacer under my 650dp. I wonder if I really need it as injectors are supposed to do that.. Cleveland intake

temp is the only thing that makes me want keep it. Any thoughts?

I'll do similar too regarding wiring separation, except my battery is located in trunk, so I'll pass the 2 main feed of the unit thru body as I did for the positive battery cable. Where did you tap the key-on 12 volt to prim the pump that stays on during krank? Or did you use the coil positive wire?

Are you letting the system control the timing or is it as I plan first do, let it mechanical? If i'm very happy with it, I'll prolly go for the Holley distributor at some time, but for now, as the whole package was pricy enuff, I want first keep my current coil/distributor combo as its in perfect condition and see how that goes.

Most important: How does the baby feels after the install? Very curious about fuel consumption too, my 4v is so thirsty I always wonder if there is actually air mixed with it...

Must be awesome to start and get that raw idle music with no pedal pumping :)
Click to expand...
I used a -6an tube fitting off the stock feed line that goes to the pump and I used a bulkhead fitting for my return line. There wont be pressure in the hose prior to the pump so it would be ok to just use rubber hose and worm clamps for that. 

As for the spacer; I would try it with and without and see what feels better to you; I have seen some systems get a bit finicky with some dual plenum manifolds. Mine has a Edlebrock Torker single plane. 

For my 12v power tap I used a port in a plug that was already present in my engine harness it is possibly the coil + wire. My ignition has all new wiring so this plug was left unused; I just probed for a keyed 12v source that stayed on when the starter was turning over. 

Fast's 1.0 system does not have timing control; but if it did I would be all over getting that set up; awesome functionality to be able to control timing electronically; but probably worth getting it running first then tackling the timing control. You may be able to get some other cheapo distributor and modify it to work with the sniper timing control; as long as you can lock out any advance systems it should theoretically be able to work. 

I havent gotten to actually drive my car all that much but the ezefi runs awesome; the idle tamed way down and is not as rich as it had to be off the old 750dp. Throttle response is awesome and it really runs better then it ever has. It's not a really noticeable overall power increase but it really made it more manageable to drive.

 
@NewAgeMuscle, that's the part i've ordered from Summit.

LOK-KD-2FMXHT, Automatic Transmission Kickdown Kit, Carburetor, Ford, FMX, Kit (Mfr. #: KD-2FMXHT)

They also have a universal version for the FMX, here the full list from Lokar.

http://www.lokar.com/product-pgs/throttlecables-kickdowns/tc-kd-pgs/tc-kd-pn.html

As I wanted order from CJ first, I got their tech line and they assured me the kit has the ford kick down,

but I also got Holley on phone next day regarding their distributor integration and they denied it was true.

Because I needed other parts that were not avail from CJ, I went for Summit in the end.

Summit got all my order except the unit, which is on back order, supposed to ship end of june :(

---> Will be very helpful to have another person going through the Sniper install at the same time

chances are high I'll see your install before you see mine. I'll follow your lead!

Vids and picts will be most welcome!

@iceberg, sounds indeed like the original coil+ wire.

The Holley unit offers a target idle speed, in case you have same option, which target did you set?

I have seen some systems get a bit finicky. What do you mean by that?

I do not see why this design would introduce an issue.

http://www.fordforums.com/f497/351c-4v-offenhauser-intake-help-165568/

 
I currently have my target idle set at 850rpm; the self tuning system started with the idle higher (around 11-1200) and slowly worked its way down as it warmed up and did some learning. I did have to feather the throttle to keep it running up to operating temperature the first time I started it. As it is now it idles at around 950-1000 in park and right around the 850 set-point when in gear. I may try dropping it a bit at a time until it gets to the point where it doesn't want to idle.

Most of the carb replacement self learning efi systems cant see where the fuel is going; and cant control which injectors are actually firing at a given time. I recall coming across a thread where a guy with a dual plane was driving his car for some time and it felt great but when he went to look at his plugs some cylinders were lean and others were rich. This would even out and give a desirable 02 reading for the system. He switched to a single plane and reported the car ran noticeably better.

There was also the engine masters video where they tested a bolt on efi system (holley terminator) vs a carb and could not get it to respond well with the dual plane. https://www.youtube.com/watch?v=2sQJPZYSoUI they start having issues around 7:30

All that said the Offenhauser is not the same design as the basic dual plane designs and most of the time they work just fine. Just a bit of insight as to why it could potentially be finicky. All of these systems are advertised to support dual plane intakes.

 
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Thanks for clarifying that. makes sense, and is indeed highly depending on the manifold design. I guess I'll know for sure in a not too far future... that's also +1 for the spacer, which would allow bit more spreading over the two planes aspiration. If I get backfires, i'll have a good hint.

 
I plan on using the RobbMc PowerSurge II for my application using the charcoal canister line as the return and a vented fuel cap to prevent the gas tank from being pressurized.
Click to expand...
The charcoal vent line on top of the tank connects to a nipple with a very small internal orifice. You may want to consider either drilling this orifice to match the ID of the nipple or adapting a sending unit on top as a return. I dont know if the vent cap will be able to handle the fuel return without modification. In my case i used an older sending unit, which fits right on. I removed the float and wiring, and used the tube to connect the charcoal vent line. I think this works great because the return fuel will flow through the tube back into the tank instead of "cascading" from the top reducing the amount of bubbles. When i did this i redirected the tube to point towards the opposite side of the pickup.

Sent from my SAMSUNG-SGH-I337 using Tapatalk

 
Last edited by a moderator:
@NewAgeMuscle, that's the part i've ordered from Summit.

LOK-KD-2FMXHT, Automatic Transmission Kickdown Kit, Carburetor, Ford, FMX, Kit (Mfr. #: KD-2FMXHT)

They also have a universal version for the FMX, here the full list from Lokar.

http://www.lokar.com/product-pgs/throttlecables-kickdowns/tc-kd-pgs/tc-kd-pn.html

As I wanted order from CJ first, I got their tech line and they assured me the kit has the ford kick down,

but I also got Holley on phone next day regarding their distributor integration and they denied it was true.

Because I needed other parts that were not avail from CJ, I went for Summit in the end.

Summit got all my order except the unit, which is on back order, supposed to ship end of june :(

---> Will be very helpful to have another person going through the Sniper install at the same time

chances are high I'll see your install before you see mine. I'll follow your lead!

Vids and picts will be most welcome!

@iceberg, sounds indeed like the original coil+ wire.

The Holley unit offers a target idle speed, in case you have same option, which target did you set?

I have seen some systems get a bit finicky. What do you mean by that?

I do not see why this design would introduce an issue.

http://www.fordforums.com/f497/351c-4v-offenhauser-intake-help-165568/
Click to expand...
Awesome thanks for the part number looks like that's what I'll be going for too. At the time I ordered, CJ's livechat said they had 3 in stock so I'm hoping to get mine in the next week or so yes looks like I'm going to begin the install first ... ::help::  Hopefully all will go well, I'll make sure to follow up with my steps and issues!

 
I plan on using the RobbMc PowerSurge II for my application using the charcoal canister line as the return and a vented fuel cap to prevent the gas tank from being pressurized.
Click to expand...
The charcoal vent line on top of the tank connects to a nipple with a very small internal orifice. You may want to consider either drilling this orifice to match the ID of the nipple or adapting a sending unit on top as a return. I dont know if the vent cap will be able to handle the fuel return without modification. In my case i used an older sending unit, which fits right on. I removed the float and wiring, and used the tube to connect the charcoal vent line. I think this works great because the return fuel will flow through the tube back into the tank instead of "cascading" from the top reducing the amount of bubbles. When i did this i redirected the tube to point towards the opposite side of the pickup.

Sent from my SAMSUNG-SGH-I337 using Tapatalk
Click to expand...
A little lost trying to understand what you're saying. The orifice on the gas tank is too small to act as a return for the RobbMC PS tank? And the vented gas cap won't be able to prevent the gas tank from becoming pressurized?

 
Sounds like he's saying that because the orifice size for the charcoal vent is quite small that it could become a restriction as a return line. Sounds like a fuel sender (stock feed tube) fits the hole and leaves you with a larger size inlet.

 
The vent line should not be used for a fuel return line without modifying the vent cap on top of the tank. The vent cap was design to transfer vapors, not a liquid.

The stock fuel cap is not vented, due to emission requirements, and is why the vent line runs to charcoal canister.

 
I plan on using the RobbMc PowerSurge II for my application using the charcoal canister line as the return and a vented fuel cap to prevent the gas tank from being pressurized.
Click to expand...
The charcoal vent line on top of the tank connects to a nipple with a very small internal orifice. You may want to consider either drilling this orifice to match the ID of the nipple or adapting a sending unit on top as a return. I dont know if the vent cap will be able to handle the fuel return without modification. In my case i used an older sending unit, which fits right on. I removed the float and wiring, and used the tube to connect the charcoal vent line. I think this works great because the return fuel will flow through the tube back into the tank instead of "cascading" from the top reducing the amount of bubbles. When i did this i redirected the tube to point towards the opposite side of the pickup.

Sent from my SAMSUNG-SGH-I337 using Tapatalk
Click to expand...
A little lost trying to understand what you're saying. The orifice on the gas tank is too small to act as a return for the RobbMC PS tank? And the vented gas cap won't be able to prevent the gas tank from becoming pressurized?
Click to expand...
Don and Iceberg are spot on. The nipple of the vent cap on top of the gas tank has a small orifice that reduces the diameter of the conduit. Therefore, you have to either drill the nipple or use a stock sending unit in its place. The sending unit fits right on and you can use its tubing to connect the vapor line. Whichever way you decide to go you will have to take the tank down, which should be a very easy task. The worst part of the job is draining the gasoline, specially if your tank is not empty.

I circled the vent cap we are talking about.



 
Sounds like he's saying that because the orifice size for the charcoal vent is quite small that it could become a restriction as a return line. Sounds like a fuel sender (stock feed tube) fits the hole and leaves you with a larger size inlet.
Click to expand...
Ah I understand now thank you.

The vent line should not be used for a fuel return line without modifying the vent cap on top of the tank. The vent cap was design to transfer vapors, not a liquid.

The stock fuel cap is not vented, due to emission requirements, and is why the vent line runs to charcoal canister.
Click to expand...
Well good thing I asked you guys first, was not aware I had to modify the cap on top of the tank. As for the fuel cap I had ordered an aftermarket "vented fuel cap" from CJ PonyParts to account for that.

 
The charcoal vent line on top of the tank connects to a nipple with a very small internal orifice. You may want to consider either drilling this orifice to match the ID of the nipple or adapting a sending unit on top as a return. I dont know if the vent cap will be able to handle the fuel return without modification. In my case i used an older sending unit, which fits right on. I removed the float and wiring, and used the tube to connect the charcoal vent line. I think this works great because the return fuel will flow through the tube back into the tank instead of "cascading" from the top reducing the amount of bubbles. When i did this i redirected the tube to point towards the opposite side of the pickup.

Sent from my SAMSUNG-SGH-I337 using Tapatalk
Click to expand...
A little lost trying to understand what you're saying. The orifice on the gas tank is too small to act as a return for the RobbMC PS tank? And the vented gas cap won't be able to prevent the gas tank from becoming pressurized?
Click to expand...
Don and Iceberg are spot on. The nipple of the vent cap on top of the gas tank has a small orifice that reduces the diameter of the conduit. Therefore, you have to either drill the nipple or use a stock sending unit in its place. The sending unit fits right on and you can use its tubing to connect the vapor line. Whichever way you decide to go you will have to take the tank down, which should be a very easy task. The worst part of the job is draining the gasoline, specially if your tank is not empty.

I circled the vent cap we are talking about.

Click to expand...
Awesome thank you for the diagram. So the thing you've circled is the sending unit correct? I've looked at the part, here  http://www.cjponyparts.com/fuel-tank-sending-unit-1971-1973/p/FSU4/ but can't seem to figure out where the vent orifice is (I'm new to all this thanks for your patience).. And what you're saying is to add a second sending unit to use for the return line?  I was planning to do the install without removing the tank, but if I'm going to have to take it out regardless do you guys think I should abandon the surge tank setup and go with an in-tank pump like a Tanks Inc one instead?

EDIT: So my understanding is the FiTech Command Center needs a vent line not a return line like the PowerSurge, so would the FiTech vent line work with the smaller orifice as it is only returning fumes and a limited amount of liquid gas? The PS requires a minimum 1/4" return line back to the tank, so I'm assuming the orifice is smaller than that and that's why you guys are concerned?

EDIT 2: Also was thinking, could I just plug the current vent orifice and weld a bung onto the filler neck and connect my vent line to that instead? Would be easy to do and eliminate the need to empty/cut the gas tank up.

Thanks for the help,

Adam

 
Last edited by a moderator:
mmm, looks like i'm gonna have to look at this in details too, as I was given the info I could connect without mods for the return line. Thx for the info.

After I saw the spec of the RobbMc PowerSurge II, one line caught my attention. it said the pump is submerged which makes it very quiet...

As I will use the Holley fuel pump from the kit, this baby will be dry and in 'air'. I have no idea about what to expect "decibel" wise.

I plan build some bracket/protective casing for the pump and the two filters behind the tank, I wonder if the pump will make noise

because it's a noisy device or if the noise is caused by the vibrations passed on to body? In case it's mostly vibs, I guess a good dose of rubber insulation for all bracket connection

to body would do the work up to a certain level, but if its a noisy pump by design, what would be a good way to reduce it?

Also I have no idea if the pump gets hot. I can imagine it's cooled down by the fuel it pumps and ambient air, but if protected for sound, will it not get too hot???

 

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