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Discussion Starter #1
Hi Guys,
I'm thinking of taking the plunge & go with an EFI system,
I'm looking to purchase the,
Holley 550-511K Sniper EFI Self-Tuning Master Kit
This will be fitted on my 68 fastback with the 351c, Full MSD ignition, long tube headers, edelbrock torker 351 (2760). Comp Cam 32-225-4.
what should i expect regarding power/mpg
would i be able to control timing through the sniper with this set up
Tell me your thoughts/ recommendations
 

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You might have some issues with that cam. 110 LSA is the absolute minimum and even that could cause vacuum signal issues. Before plunking down the money, check to see how much vacuum you have. I suggest calling Holley and talking to them first. I’m going through this right now.
 

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Discussion Starter #3
You might have some issues with that cam. 110 LSA is the absolute minimum and even that could cause vacuum signal issues. Before plunking down the money, check to see how much vacuum you have. I suggest calling Holley and talking to them first. I’m going through this right now.
Thanks, email just sent to Holley.
 

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You might search Sniper on this forum. Within the past 2 months several threads on Sniper problems. FITech and Summit too.
So much so that I'll prob go with the Edelbrock ProFlo 4 if I decide to shuck my stock Mustang 5.0 EFI.
 

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Holy ****, just say No! Worst mistake I've made with this car.

Baloo, don't you dare shuck that 5.0 EEC-IV.

I will have some strong words for Holley on Tuesday. Garbage system. Should never have made it to market. Can't believe there isn't a class action or some such. Definitely wished I had tried the Edelbrock. That thousand bucks you save with the Sniper will come back to haunt you.
 

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After rereading the original post, I’m getting as bad as everybody else about not thoroughly reading posts, the OP has a 351 Cleveland and I don’t think they make a Pro-Flo 4 for that application. The GT 390 threw me off.
 

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After rereading the original post, I’m getting as bad as everybody else about not thoroughly reading posts, the OP has a 351 Cleveland and I don’t think they make a Pro-Flo 4 for that application. The GT 390 threw me off.
It's okay, you inadvertently helped me! Didn't know Edelbrock made that style of EFI for an FE :).
 

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I have a sniper on my 450hp 331. Its been fine. The only issues I had were self induced. It is sensitive to EMI, but with some careful consideration to routing wires and plug wire choice and it's a solid system.

You can control timing if you run a dual sync dizzy, but they recommend their Hyperspark as it integrates so much easier. I have a stock '65 dizzy with a pertronix in mine. I'd say the system helps me achieve a little better mileage, probably more attributed to my .63 overdrive. But it's the cold starts and actually all the easy starts that make it worth it. No stumbles. no weirdness. Get it, turn the key and drive. Make a change? the system will learn.

All of my friends who have tried to run the FiTechs have had difficulties and their customer service/help is non existent.

I think the MSD atomic and the Pro flo are kinda ugly myself.
 

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Discussion Starter #11
Has anyone else had issues with having a higher lift cam fitted, like what Quicksilver 66 has mentioned above.
 

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I have a sniper on my 450hp 331. Its been fine. The only issues I had were self induced. It is sensitive to EMI, but with some careful consideration to routing wires and plug wire choice and it's a solid system.
Sometimes.. Sometimes not, judging by what I'm going through, and tons and tons of others by searching. It's just not worth the crap shoot.
 

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I have installed a Sniper on my '66 289 with Edelbrock dual plane intake, 1" spacer, MSD distributor, wires and 6AL box. No timing control and no problems.
 

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Has anyone else had issues with having a higher lift cam fitted, like what Quicksilver 66 has mentioned above.
Cam Lift is not the issue on efi, it's overlap.
 

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Has anyone else had issues with having a higher lift cam fitted, like what Quicksilver 66 has mentioned above.
As @cj428mach said above, it’s not about lift, it’s about vacuum. Cams with smaller lobe separation angles (LSA) have less vacuum, since the intake and exhaust valves are open at the same time. This is also what gives your cam that thump. The EFI system uses the vacuum signal to do its thing and if there’s a low signal, the system can get confused. Supposedly 110 LSA like your cam (and mine) is the absolute minimum (but 112 is better). That being said, I’m dealing with a wicked off-idle stumble in my car that makes it look like I’ve never driven a clutch before. Not certain it’s an issue with the cam yet, but I have my suspicions. Good luck.
 

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The holley reps do say, less than 9in of vacuum and the system will not be very happy. My cam has an LSA of 112. Even with the lift and duration being up there, it still makes 14-15in at idle. We ran a Lunati cam before the current one in it from Howards that had about 9.. I never put the sniper on as I knew it would not be happy. The previous Lunati cam in the car had an LSA on 114.

They do have a tendency to expose other problems that may be masked by a carb. I had a mild intake gasket leak and an exhaust leak that caused me issues initially. Wiped out the Oxygen sensor with the exhaust leak. A decel pop by the intake leak that I chased and kept expecting it to be the sniper. Nope. All on me.

Initially I had a start issue, but I'd wired it in such that it did not get signal in 'start' only in 'run'. Oops. Again, all on me.

The two things that I think Holley did poorly though. Throttle actuation. That arm is WAY too short for any performance applications making the cars super jerky. Low quality sensors. Lots of threads on people having CTS, Oxygen and Map sensors in them show up bad. Thankfully they're usually pretty good about replacing them.

I do read a lot on the forums and see a lot of people have issue with aftermarket timing control. But I think the move to either a stock dizzy/pertronix or the hyper spark make that a non issue too.

I think my point is this, its a fine system built to a certain price point and there are (like any other) people who run in to troubles with them. I'd hazard a guess that 60% are pre existing issues magnified by the install. 20% are install errors, 10% sensor faults and 10% other.
 

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Not sure what to say, except there are a lot of us (just do a search on the Holley forum. Most of the unsolvable ones are SBFs) that have EMI issues that cannot be solved. (Without adding shielding). Some people get lucky I guess, or it depends on a combination.
Some issues are caused by rushed installs, no doubt (like your start/crank wiring). Some are not.
 
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