Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Thanks for posting this info.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Great write up and videos! this is definitely making me rethink my plan for my truck. I was planning to drop a TBI 350 with a 700r4 in my 72, but now think the extra headaches may not be worth it.
How do you guys think the sniper or FiTech systems compare to the late 80s tbi for power, drivability, etc?

Thanks,
Jim

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

I went and looked at prices. Am I mistaken that these systems are $3500, plus or minus? Not picking on anyone, just trying to be sure about costs.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

They run about $1000.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Old gold.
I think the big advantage these new units have over the older tbi units is much more computing power. Which allows an ability to self learn and more accurately compensate for different conditions.
That is my understanding

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

I was looking at FI tech for a while. I read their support went downhill with the large volume of sales then ended up getting. With Holley, it's a big company and I feel I can get better support.


$1000 plus $300 for the optional fuel system.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

I just finished the Install of the sniper EFI on my 72 K10 yesterday, You're going to love it!

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

I'm about to call Holley for a support question. Maybe you can chime in. The Yellow wire from the Holley harness is supposed to measure RPM. Do I hook it up to the same wire that goes from my distributor to my tach (brown wire)? The instructions are not 100% clear to me.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

I have an MSD box, so the yellow wire was not used, so i wont be of any help sorry!

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Holley told me I have to use the brown wire on the optional 10 pin connector to now go to my tach. The yellow wire on the 7 pin connector will go to where my original tach signal came from on the distributor.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Aus79c20 and Ekliptix, thanks guys, I think I'm headed down this path!
Jim

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Made some wiring progress tonight.
https://i.imgur.com/3q2ZNhyh.jpg

This is an optional 10 pin connector. Most of the wires are for nitrous, etc, so I cut and heat shrinked most of them. I only need the brown wire remaining to send a signal to my tach.
https://i.imgur.com/aVkjyksh.jpg

Started getting some things tucked away. I need to buy some black wire loom to cover those 3 wires at the top. I attached the fuse and relay to a screw by that AC box thing.
https://i.imgur.com/L3neJOqh.jpg

Tried to hide the wires as much as possible. This is the power from the battery, ran through the fender.
https://i.imgur.com/L2I07i2h.jpg

What's left is connecting a blue wire (power) to the fuel pump, grounding the fuel pump, ensuring the O2 sensor cable is secure, terminating the yellow wire to the distributor tach signal, connecting the brown wire to the tach, connecting the pink wire to 12v when the ignition is on.

Then put some gas in the tank, follow the start up instructions including priming the pump and dumping gas into a can to fill the source hose with fuel.

The end is in sight!

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Lookin good. I’m anxious to see how it does with that big cam and low vacuum.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Yea, I have not 100% identified what the low vacuum is from. This EFI unit won't fix a vacuum leak but i'm not sure if that's what I have.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Good news and bad news.

The good: The truck is running!!! It idles super smooth and there's no unspent fuel coming out the exhaust.

The bad: There's coolant leaking from the intake manifold where a crack has appeared, likely from me over tightened the heat temp sensor.

Need to do:
1) replace/fix intake manifold where it cracked.
2) adjust throttle cable to provide 100% open throttle. Reads 85% position at peddle WOT.
3) wait 3 months for snow to melt

Part 3 Video: https://youtu.be/JSnHy1DTm8E

Finished engine bay
https://i.imgur.com/qaTdR0bh.jpg

Running and warming up
https://i.imgur.com/1eLElLsh.jpg

Me "What's that sound?"
https://i.imgur.com/fnm3wZph.jpg

Green juice is good, right?
https://i.imgur.com/iVzCDe2h.jpg

Random pic of chains used to get 1 car and 2 trucks unstuck from my driveway this weekend. 305 studded winter tires, love 'em.
https://i.imgur.com/6fV4j3Xh.jpg

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Actually the FiTech systems start at $795. I've got two Fitech systems installed. One on my supercharged 70 GMC and another on my 67 Cutlass with a 468 BBC. I installed the FiTech on the Cutlass over two years ago. I'm using the FCC on the Cutlass without issues. The problem with the FCC is most people mount it on the firewall or near the exhaust. My is mounted directly behind the left headlight. Never had a problem with it. Both units are performing flawlessly. I'm very happy with FiTech EFI.

As far as tech support the few times I've called they have answered quickly and answered my questions. I don't call on Mondays since that is their heaviest call volume. There is a Facebook FiTech Owners group that has great info and help. It appears most problems are user who can't follow instruction and cause their own problems.

$795 -FiTech Go Street EFI 400HP Self-Tuning Fuel Injection Systems 30003

70 GMC Supercharge 350
https://farm5.staticflickr.com/4719/...1d94551c_c.jpg

67 Cutlass 468 BBC
https://farm5.staticflickr.com/4330/...db684bcc_c.jpg

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Good video bud. The truck sounds good. I may have missed it but what size cam are you running and how much vacuum are you pulling? The sniper is the route I’m going I just need to find a cam that’ll pull enough vacuum. Thanks.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

I'm trying to find my cam specs, but this is what the holley instructions say:

Stock/Mild = This selection will work well on most applications equipped with stock or “street performance” camshafts. Choose Stock/Mild If you are unsure of your camshaft specs.

Street/Strip = Select this if your engine has between 8” and 13” of manifold vacuum.

Race = Select this if your engine has less than 7” of manifold vacuum. Race oriented camshafts may require laptop tuning for optimal idle stability.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

I’ve been looking for that info and couldn’t find it. That’s doable. Thanks bud.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

Looking good so far. I’m also installing a few sniper EFIs on a few customers vehicles. On that 10 pin connector I went further and removed the actual pins from the harness and installed the correct cavity plugs in connectors. I can post the part numbers and tool needed to do that if you’d like. On the 67 I will be doing I’m going to have the stock tank cleaned and have bungs put on bottom of it. Your not afraid of fuel issues with the pump having to pull from stock line as well as starvation issues?

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

I'm impressed how quickly it fires off - I have an older BigStuff3 system which uses dual sync (cam and crank) for sequential injection but that in turn means the engine has to go through one and perhaps two full revolutions before it can fire off while cranking.

This one seemed to light off right away, which is much nicer!

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

I'll pass on the pin remover for now, thanks.
Regarding fuel starvation with the stock line/pick up, the EFI unit won't consume any more then a 750 carb so I can't imagine an issues. The engine previously dynoed at 430hp. Thoughts?

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

the 750 carb also has float bowls that store enough fuel to cover you in the event that fuel sloshes away from the tank pickup while cornering etc., which is a luxury you don't have in a high pressure EFI system... Probably fine if you never have less than 1/3 of a tank though...

Historically solved with surge tanks and so forth, but you'd be doing me a big favor if you tried out a holley hyrdamat in a stock tank and posted results :D

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

In my previous 68, I ran a 454 with a hopped up GM TBI using the stock pickup tube and in-cab tank and it never sucked air. I ran the tank pretty low a few times just to see. It helps that it is such a tall and narrow tank.
My Caddy tank has similar dimensions but is flat under the trunk floor. I had to add a sump or it would suck air at anything less than 1/2 after I put efi on it.

Re: Install thread- Holley EFI Sniper on '72 402 big block
 

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