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Holley Sniper EFI on my Nailhead


RockinRiviDad

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Woo WHOO!! I now have about 3500 miles clocked on my Nailhead. Approximately, 2500 of these miles are with my EFI. 

 

I LOVE that is still resembles a carb. Simple & clean. With my air cleaner on guys at my local cruise-ins are blown away haha

 

My carb was 600 cfm’s. This EFI throttle body is 800 cfm’s. I’ve read that our Nailheads LOVE cfm’s & this 800 cfm sure made a difference haha

 

I purchased the Master Kit which includes the external Holley fuel pump, mounting hardware & hoses. This made it easy. 

 

I really enjoy how I can simply fire my car up & drive it now. I was not that lucky with my carburetor. 

 

I paid a reputible shop to do the install & I am pleased with their work. I was hoping that by hiring a pro I would avoid some headaches. Unfortunately, I still had a few problems which I sorted out. Overall, I am glad I made the switch. 

 

One problem was that the O2 sensor was not welded correctly. The kit comes with an O2 bung, high temp gasket & quality straps to hold it in place. The shop said welding it in would be better. Well the weld job sucked & it was leaking. I didn’t catch it for a while due to the placement the shop chose. They put it kind of close to my frame rail. Not sure why. That is probably why they couldn’t weld around it right. Instructions call for placing O2 sensor “as close to engine, generally 6-8” from collector”. The shop placed mine further than that. Not sure why? Obviously, I will have to go have a talk with them. 

 

I’m good for cruising with this setup. But another detail I learned is that the second half to any EFI is to pair it with an electronic distributor. Holley has one for our Nailheads on their website. So I will do some homework & see where this goes. 

 

Edit: forgot to mention, the ECU is built into the TB. It sits just behind the nameplate on the face of the TB. 

 

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Edited by RockinRiviDad (see edit history)
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On 12/28/2018 at 6:30 PM, RivNut said:

Looks good; sounds like you're a happy camper.  How did you retain the linkage for the kick down and switch pitch? 

 

Thank u.

Funny u ask. “Retain” didn’t just happen, it was a bit of a struggle. Linkage was actually problem #1 & kick down/switch pitch was problem #2 haha.

 

After the initial install of the EFI there was no “easing into the throttle”. It was either ON (full throttle) or OFF (no throttle).

 

It turns out that the factory mechanical throttle linkage angles on some old cars do not play well with some TBI’s or aftermarket carbs. Our cars have that kind of linkage. So I needed to change that angle. I spoke to a couple of shops & they all said they always fabricate brackets. I am NOT a fabricator but I thought “how hard can that be” right? 

 

I had a hell of a time figuring it out. I went thru 5 brackets just to get the throttle linkage right including one store bought Holley bracket. I was so focused on throttle that I forgot about the kickdown/switch pitch. Then I made 2 more brackets that would accommodate the KD/SP before I figured out that I was mounting the KD/SP wrong...UGH!!! Lucky for me a neighbor showed up just before I torched my car in frustration haha. He offered to help modify the Holley bought bracket with his welding skills & WAH-LAH!! It worked...still gotta get that washer in place

 

Lots of learning...but I’m learning 

 

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EDIT 01/2020: DO NOT forget to check your TPS (throttle position sensor) after U install your bracket. I had to reconfigured my homemade throttle linkage bracket. U can see by comparing above pic to the one below that I moved linkage mount 3/4” forward to get more range. I had mine set at 97% @ WOT on my old bracket before I made a bracket to incorporate my kickdown. It never dawned on me to RECHECK my TPS. Now that I did I found that my kickdown wasn’t allowing full throttle. I was only getting 76% @ WOT…Ugh…I cut off top of bracket & had my neighbor weld on a piece of 1” angle iron, I drilled new mounting hole & cut away excess metal to avoid contacting rotating parts. I was able to achieve 92% @ WOT after all done. The kickdown still limits throttle travel. I was considering using an aftermarket kickdown switch. But after my test drive I am good with 92%…that is plenty good. I can FINALLY do burnouts.

 

i hope this helps keep others from learning the hard way like I am 

 

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Here is another idea that might have been easier to do from the start. This is the Holley bracket I started with. If I would’ve cut this bracket like I did but rotated to point forward (to the left as it sits in this pic) before welding it that might’ve given me the throttle range I needed. Live & learn. Hope this helps someone. 
 

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Edited by RockinRiviDad (see edit history)
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14 hours ago, RoadShark said:

Where is the fuel pump mounted?  Does it make a lot of noise?

 

Good questions. 

 

Fuel pump is mounted to inside frame rail, behind the rear axle on driver side. Instructions recommend to mount as close to sending unit as possible (within 24”).

 

Holley actually recommends internal fuel pumps which last longer & are more efficient. But I did not think that was possible on our cars. I have since learned that universal internal fuel pumps (which mounts inside fuel tank) are available from a few company’s (Aeromotive is one). I spoke to an  Aeromotive rep at a show & he claims it would totally work on our cars. 

 

I wouldn’t call my external pump “loud”. But it makes noise, u can hear a hum/buzz. At idle & music off I can hear it. It’s not bad. And in my case, I still don’t have all my interior installed. I’m still lacking carpet & padding. I’m sure that will help muffle the hum. I may switch to an internal pump if/when my external one takes a dump. 

 

Pic #1: external fuel pump

Pic #2: inline fuel filter between sending unit & pump

 

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Way to go, David!      You will not be sorry.    I have run EFI on my 1950 straight eight for 15,000 miles.   Color me happy. 

 

  Couple of observations  

 

  The fuel pump will quieten  down if isolated more from the frame. Mine had the hum when mounted as your's .  I bought an exhaust clamp with rubber between the clamp and a metal strap. Auto parts store.  Bolted the strap where the pump strap is now fitted.  Clamped the pump in the clamp. The strap can be bent into whatever shape needed.  No more noise. At all.

 

 You are correct on the distributor .  LOTS of difference.  I had the original distributor modified.  All the guts were removed. A GM magnetic pickup was installed.  Using GM 7 prong module mounted on the cowl. Can go anywhere.  Hidden if one wishes. 

 

  Ben

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Examples of my shotty throttle linkage fab work before realizing I forgot about my kickdown switch.

 

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Here is an example of what I  came up with to attach my kickdown. The problem was I had the kickdown mounted for the arm to pull out as the throttle was pulled back (accelerating). The arm is suppose to travel inward when accelerating.

 

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Edited by RockinRiviDad (see edit history)
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19 hours ago, PWB said:

Nice! Such a clean look.

Now I wish someone would reproduce the dang bellows sleeve for the switch arm.

I’m sure there’s a lot of Buick owners that can use a new one!

 

 

 It is reproduced , available from Inline Tube.

https://www.ebay.com/itm/1965-66-GM-All-Models-T-400-Transmission-Kick-Down-Rubber-Boot-GTO-442-Chevelle/201567476446

 

  Loren

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I forgot to mention, one detail that the shop I used pointed out was that both main fuel line & return line needed to be 3/8”.

 

My car is a factory A/C car which requires a main & return fuel line. My plan is to add A/C someday. So I had already bought a pre-bent fuel line kit from a fuel line vendor. This fuel line kit I bought & installed was a big step in the right direction. Or so I thought…

 

That was NOT the case. Factory fuel lines for my A/C car is 3/8” for the main line & 1/4” for a return. I woulda probably tried to use the 1/4” line without knowing any better & something coulda went wrong. Glad the shop figured that out early & ran a new line. 

 

The EFI kit comes with all the fittings u need for this step too. Here’s a couple pix

 

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The rubber isolators Ed pictured MAY reduce noise, but are not the best. You have to install a through bolt. The better ones have a stud molded to each side which are completely isolated from ANY metal with NO through connections.  They can be found at foreign car distributors of parts. Most commonly used on MGB's & others for fuel pumps.  Add the isolated straps & there should be NO NOISES or VIBRATIONS.

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  • 1 month later...

Hy David

 

I am new to this site . Can you tell which difference between before and after conversion to the Holley Sniper EFI you have, in fuel consumtion (mpg or l/100km), throttle Response and engine Power. I would like to do a conversion on my 65th Riviera too.

You know any other guy, he goes with a modern Injection on a old nailhead like you.

 

 

Greedings from Germany

Toni

 

 

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That is very cool! Could you tell me the Holley part #? Is it 550-511 (EFI 4150 4--Barrel Self-Tuning Master Kit?). I found in Speedway catalog-their part #425550511K $1,259.99? I'm very interested in converting my '64 Riviera NailHead. Have you checked gas mileage compared to stock? Many Thanks-great pictures and information

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On 2/6/2019 at 4:27 AM, oldy65 said:

Can you tell the difference between before/after conversion to the Sniper EFI, in fuel consumption in mpg, throttle Response and engine Power. 

 

You know any other guy, he goes with a modern Injection on a old nailhead like you.

 

Toni

 

Welcome to the forum Toni. 

 

Sorry. I do NOT have a comparison of my fuel mileage. My car was parked for over 13 years. Then when I finally got her running again I was having all types of issues with my carburetor before I switched to EFI. 

 

I had issues with throttle response. Then I discovered it was a linkage issue. So I fab’d up a linkage plate. I provided pix in this thread. 

 

My carb was 600cfm. This TB (throttle body) is 800cfm. Engine power? YES!! I can sure tell a difference. Me likey haha

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On 2/7/2019 at 3:49 PM, frenchy51 said:

That is very cool! Could you tell me the Holley part #? Is it 550-511 (EFI 4150 4--Barrel Self-Tuning Master Kit?). I found in Speedway catalog-their part #425550511K $1,259.99? I'm very interested in converting my '64 Riviera NailHead. Have you checked gas mileage compared to stock? Many Thanks-great pictures and information

 

Your welcome

 

Yes, the Master Kit is what I bought. Kit #550-510K

 

I have no clue what stock gas mileage is. My car was parked for way too long to remember. Sorry. 

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My '64 that has always been well tuned averages about 12 or 13. It might do better on a long trip but I can't remember driving beyond 100 miles since I have owned it. My '60 Electra does about the same, well tuned with a tight Dynaflow. I drove the '60 out to Flint in '03 and got 16 driving steady on the QEW.

 

I took a look at the Snipers online. If something happened where I needed to replace my carb I would probably consider the conversion. There are a lot of factors that go into fuel mileage so I wouldn't expect a dramatic change there, maybe 1 or 2 MPG. Better mileage comes from overdrives, usually 2 of them.

Bernie

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Go the whole 9 yards.  Electronic ignition, roller with roller lifters, roller rockers, EFI, and a lock-up overdrive transmission.  At the Eureka, AR meet in 2005, one ROA member drove his 700-4R equipped '63 from South Carolina and reported getting 23 mpg.  If the 57 6 quart pan will fit the Riviera chassis, add that and only run the 5 quarts of oil in it.  Keeps the crank from slapping oil causing it to lose hp. A little larger diameter tire and keep the speed lawful and someone might be surprised what they could get. 

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  • 2 months later...

Update:

Another detail that I learned about my Sniper EFI TB (throttle body) is that the primaries & secondaries do not work like they do on a standard carb. My TB opens all four butterflies/barrels at the same time. They call this 1:1 linkage. Not sure if all TB fuel injected systems are the same. But I found this next topic very interesting. 

 

There is tons of info online about what is called a progressive linkage for the Sniper. Aftermarket companies sell this easy to install linkage which allows secondaries to open at about 40% (varies on some cars) of acceleration. There are a few steps to follow in order to reconfigure the software & tell the ECU what is going on & what to do. That is where my head starts to spin, my vision gets blurry & limbs go numb haha. TMI haha. I’m not that smart haha. Some guys make it sound easy & some make it sound complicated. It seems that the guys who know what they are doing are using a laptop computer to reconfigure the ECU 🤷🏻‍♂️

 

Bottom line:

Some guys LOVE the progressive linkage & claim that Holley should sell the TB’s with this setup. I agree. 

 

Most guys had issues with the setup causing their cars to run like poop. So they went back to the 1:1 linkage & reconfigured the ECU to original settings. 

 

All this to say Holley actually does NOT recommend this modification haha. So if something goes wrong it’s on the user/installer. Although, the Holley Sniper apparently has a progressive linkage option in the setup/startup menu 🤷🏻‍♂️

 

My car runs great with the 1:1 linkage. The only linkage issue I had was with the angle in which the throttle pedal pulled the TB linkage. I bet some guys who want to switch to the progressive linkage only want it to fix the same problem I had. But that may not be the answer. Anyway, I thought I would post this update for those interested in going with an EFI system. 

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I do LS based engine tuning and I can try explain it how I’ve seen it in action. Please take my information just as opinion, I wasn’t doing the ECU tuning on the vehicle since I’m only familiar with HP Tuner. The vehicle in question was a modified SBC 383 maybe, with a T56 swap. It had a extremely drivable camshaft and had plenty of power down low. The problem according to the owner was that it was extremely grabby and jumpy while trying to accelerate normally. He was right - the thing was practically unusable imo. We originally joked around and thought he was one of those guys that installs a 6 puck race clutch in his daily driver but after driving it we resized he had another problem. 

 

We originally looked into the vehicle throttle cable, some have complained that the Sniper return spring is a bit aggressive and you could visibly see the tension it placed on the lever from the pedal in the engine bay. We saw strange twisting movement happening and eventually ended up getting replacement bronze bushings for the pedal. This helped make the throttle more precise and not feel like you were “blindly” pushing the throttle. Probably not your problem but an interesting concern to look into. The problem of it being waaaay to jumpy down low was still there.

 

I can’t really speak too much of what we tried to do to the ECU cause the interface wasn’t similar to HP Tuner but we approached the problem the same way we would have on a LS. We would have started pulling some timing out below, oh maybe 1200 rpm??? to see if we could make it chill out a bit. But the Sniper, in his application, was relying on a signal input from an aftermarket distributor and if we pulled timing out at idle we would have be pulling it out across the board... not a good solution. We ended up purchasing a adjustable secondary linkage to try and settle it down after researching our issue. We think we left it on the most minimal setting or maybe 1 up from the basic adjustment and worked perfect. We pulled some fuel out based on throttle position to keep it from going rich. The ECU assumes it will always have a fixed airflow but down low the linkage changes that relationship. Once that was squared away it ran like a top. This was a few years ago and since then it looks like Sniper has released a patch/selection in the tuning software work with these kits. Hope this helps!

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19 hours ago, sixxer said:

Hope this helps!

 

Thx for the info brother. Sounds like u have some good experience. Some guy will surely benefit from your post.

 

I wasn’t quite sure where u were going. After I reread my post I see how it sounds like I may have had a problem. But I assure u I don’t. I fixed the mechanical throttle linkage issue & I’m good. Car runs great. I clocked close to 100 miles this past weekend driving from cruise-in to cruise-in. She drives so well now.

 

Thx again for the input tho

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