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Sniper EFI, Street Demon, or Qjet all the way

  • Sniper EFI get with the times pal

  • Street Demon, because you’re a lazy bastard.

  • Qjet all the way, all day, and bring back leaded fuel ffs

  • Why didn’t you go with a Double pumper you coward

  • Audit

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Discussion Starter · #1 ·
Hey all, as we move into the holidays, and time off becomes abundant, I’m going to do the efi or new carb upgrade. I was curious to hear Bird Guy’s (and Gals?) thoughts on this modification.

Here’s what we’re working with:
1974 Formula Firebird with 1970 face.
- 455 YC engine auto trans
- I just bought this car in October and I’m not sure what the internals look like, the YC definitely didn’t come in this car, probably out of a bonnevile or Grandville? Maybe even a GTO. The engine is strong and makes the car fly down the road very fast, even with the carb needing rebuild. It doesn’t feel like a 250 HP YC, it feels in the 300 range. I have and have had fast cars so know what to expect. The Idle sounds like she has a mild cam and the exhaust is open. Not sure what muffler it is but under the car it looks very stock. True dual exhaust tho

I bought the Street Demon because I want to drive the car around town and didn’t want to wait till I figured out the rebuild on the quadrajunk. I’ve been lectured since my high school days (I’m 36 now) by the guys who lived The muscle car life in the sixties and seventies that the qjet is trash, and at the same time the best Carb for my Bird hands down if adjusted right. I just want to enjoy it and the street demon seemed like the path of least resistance.
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here’s the set up the day I got her
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Here she is cleaned up

more to follow
 

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Discussion Starter · #2 ·
I have an opportunity to buy my buddys Sniper EFI brand new in box he stupidly bought for his salt water boat. His loss is my gain for 1000$ I have the performer manifold to bolt it to, but I’m wondering if I should return it and get the RPM performer? I’m just not sure about hood clearance with the 1970 snorkel hood? Anyway I’ve read you can get reliable power and cold start issues to go away forever. Plus the system can support up to 660 hp they say? Anyway let me know what you think.
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Here’s some additional Bird shots
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'93 6-spd Trans Am - '96 C4
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You clearly have something against carburetors. There is no choice for you to make. Have fun.
 
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“(and Gals?)”

Definitely.
 
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1977 Trans Am W72 400/4speed (swapped)
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“Anyway I’ve read you can get reliable power and cold start issues to go away forever. Plus the system can support up to 660 hp they say?”

All of those things are fairly easily attainable with a Qjet.

I’m also 36 so I didn’t grow up during the carburetor days, and admittedly initially they seemed outside of my skill set and understanding. They’re not hard. I personally couldn’t see spending the money on EFI just to have it. It offers ME nothing I don’t get out of a carb. You also have to consider the fuel pump, pickup, possibly tank, possibly lines and (as I’ve read because I don’t have any hands on experience) ensure your electrical is up to spec to avoid issues. Also ensure no exhaust leaks. Someone somewhere was just laying all of this out so I’m borrowing some from him. I can’t recall where otherwise I’d direct you there.

It’s obviously your car and money though. Also the RPM intake won’t fit under the shaker assembly.
 

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I have a 78 TA equipped with a Holley Sniper Quadrajet. Had quite a few teething issues getting it going. The biggest was RFI. But once you get past that, the performance is really nice.

Having said that, I think if I had it do over again, I wouldn't for one simple reason. Carbs, generally, won't strand you on the side of the road. EFI will. It hasn't happened to me, yet. But, if you join the Holley Sniper Facebook group you will hear from quite a few people that it has happened to.
 

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Discussion Starter · #7 ·
“Anyway I’ve read you can get reliable power and cold start issues to go away forever. Plus the system can support up to 660 hp they say?”

All of those things are fairly easily attainable with a Qjet.

I’m also 36 so I didn’t grow up during the carburetor days, and admittedly initially they seemed outside of my skill set and understanding. They’re not hard. I personally couldn’t see spending the money on EFI just to have it. It offers ME nothing I don’t get out of a carb. You also have to consider the fuel pump, pickup, possibly tank, possibly lines and (as I’ve read because I don’t have any hands on experience) ensure your electrical is up to spec to avoid issues. Also ensure no exhaust leaks. Someone somewhere was just laying all of this out so I’m borrowing some from him. I can’t recall where otherwise I’d direct you there.

It’s obviously your car and money though. Also the RPM intake won’t fit under the shaker assembly.
And this is why I’m asking the board lol. Thanks for the info. I love carbs and I have a 750 street demon in the box waiting to get installed. But the EFI deal was too good to pass up. So I bought it. I’m glad you hit me with this info so I can dig deeper. I figured it wouldn’t be all daisies. Thanks
 

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Discussion Starter · #8 ·
I have a 78 TA equipped with a Holley Sniper Quadrajet. Had quite a few teething issues getting it going. The biggest was RFI. But once you get past that, the performance is really nice.

Having said that, I think if I had it do over again, I wouldn't for one simple reason. Carbs, generally, won't strand you on the side of the road. EFI will. It hasn't happened to me, yet. But, if you join the Holley Sniper Facebook group you will hear from quite a few people that it has happened to.
To be clear RFI == Radio Frequency Interference right? Did you solve the source of it and how did you determine that was the issue?

thanks
 

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Discussion Starter · #10 ·
You clearly have something against carburetors. There is no choice for you to make. Have fun.
Pfftttt no way I have the rare opportunity to try both actually. But I wanted to get the opinion of the folks that have the exp. I was going to return the Street demon but now, I’m probably going to throw it on first and then EFI second and see which is better. I’ll be sure to do a write up for science and posterity
 

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Discussion Starter · #12 ·
I put a Sniper on my TA 2 years ago. Love it. Fires right up every time. Better fuel mileage. I have the in tank pump. View attachment 232560 View attachment 232560 View attachment 232560 View attachment 232560
That’s so rad,

I went with the EFI but I took the recommendations from some of our users.
What are you doing to combat EMI? Did you even experience emi?

I’m currentlytransitioning from my phase 2 (removal and replacement of worn items in preparation for the Sniper install)
I have everything needed to complete the install correctly:
  • sniper base system
  • in-line fuel system with pump, prefilter, post filter, ptfe lines, block off plate for factory system
  • o2 sensor installation parts
  • Holley Hyperspark Dist
  • Holley hyperspark Box
  • Holley hyperspark igniter
  • msd super conductor wires
  • msd resistor Spark plugs
  • return line components
  • new air cleaner to fit Sniper
  • fully terminated harness for easy install
  • new battery terminals
I think I’m ready to install.
I got a Pontiac Performer intake from edelbrock to mount it on as well. Here’s the mock up
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I didn't have any problems with my install. Read the directions several times and follow them to a T. Route all of the electric lines away from any ignition sources. As you can see my coil is next to the sniper but the wires are routed to the firewall , to the fender. My MSD box is behind the headlight. All other wires are run next to the sniper next to the valve cover. Only problem iI have had was a bad O2 sensor.
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Discussion Starter · #14 ·
I didn't have any problems with my install. Read the directions several times and follow them to a T. Route all of the electric lines away from any ignition sources. As you can see my coil is next to the sniper but the wires are routed to the firewall , to the fender. My MSD box is behind the headlight. All other wires are run next to the sniper next to the valve cover. Only problem iI have had was a bad O2 sensor. View attachment 232566
thanks for the tip/s yeah I’ve read the instructions 10X haha. I’m planning on running the hyperspark CD box, in the car and I got the super conductors from MSD. Along with the resistor spark plugs, and the fully terminated Harness, I think I’ll be in good shape. The only thing holding me up is the return line. I wish I would have just bought the WGI tank with in tank pump like you got. My budget was maxed out snd I have to work with what I do have.

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I’m planning on putting a bulkhead fitting on the Sending unit with a 12” submergible Fuel hose so as not to aerate the fuel. I’ve read I might need to vent the system too but I think I’m gonna get to up and running first and see if that issue pops up. The original tank has evap lines x2should be good enough as a vent.
 
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