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
 

subscribed

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

My concerns are really for the fuel pump having to draw the fuel up the stock line in sending unit then down to pump. Also as stated with a carburetor you have fuel bowls which are little reservoirs for fuel. With EFI you do not have that, A GM TBI unit can’t compare it only requires 15 psi not the 60 the efi requires. I’ve read a few people wanting to route the same way you are and landed up putting bungs on bottom of tank.

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

A pause in progress since finding the crack in the intake manifold. Got the intake off and the heads cleaned up, in anticipating of installing a replacement intake manifold. Then, everything back together, add coolant, start er up, and pick up where I left off.
https://i.imgur.com/V4kwCuuh.jpg
https://i.imgur.com/F22T6T0h.jpg

Clean left. Dirty right.
https://i.imgur.com/kBOxsKlh.jpg

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

subd

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

I fitted the Sniper EFI to the 396 in my truck and picked up a bunch of low down and midrange torque. The throttle response is way better. But the gas pedal was so touchy I had to make a small extension for the linkage where the rod hooks up.
Yours appears to be a cable so you may not have the same issue.
Overall I’m very happy with mine.
Here’s a pic of the extension

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

Cool! I'm at almost the same point, hooked up the linkage on my Sniper last night.

I'm excited to see how it drives. I had a Q-Jet on an oval port manifold on roval port heads and I've also put the port-matched intake back on so that should help as well.

I'm not doing computer timing control, did you?

Here's the fuel lines I bent up yesterday!

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

Nice work on those fuel lines.

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

Those lines look great. No timing control on my setup.

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

As long as none of my lines leak (this is my first time ever doing stainless with AN fittings) I think it'll be a killer setup. Like you, I'm going to forego timing control at least at first as well, maybe do that as a second project, but I haven't heard great things yet about it.

I haven't checked the geometry yet, I have solid pedal linkage as well. I had to drill the hole larger to accommodate the linkage though. Once installed with plastic bushings it was nice and solid, but I'll have to wait and see if I have the same sensitive pedal that you did.

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

I'm not having the computer control timing. As I understand it, I have to buy a specific distributor that has a plug in for the Sniper system. I've watched the video of the setup. It's out of my level of experience, so I'll likely get some help if I go that route in the future. I like the idea of combining EFI plus timing control to get max performance, all automatically with a computer.

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

Assuming your distributor is well set up for your engine, I don't think there's much performance advantage to be had. But it can in theory help smooth the idle by adjusting individual spark pulses. That's the only feature I'd actually like.

They give you a coil driver so that you don't have to run a full ignition box, that's kind of interesting.

I have an MSD dual sync with the same purple and green wires, but I'm not sure if I can make it work with the Holley and am a little scared of biting off more than I can chew in trying to do the install with a non-supported third party pickup!

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

A lot of people have had trouble getting their msd distributors to play nice with the timing control function. I think the Holley dual sync is probably the best option if you want to use timing control and of course more expensive than msd. For me, not worth it at this stage.

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

Got mine all up and running (not a truck, but I'll try to stick a photo in anyway). The throttle is SUPER touchy, as you say. I'll order a Holley throttle extension or make one, I guess.

Was yours better with the extension? With a deep four speed a 4.10 gears it's a little touchy to drive! By which I mean "almost impossible to drive safely" as it is. They really ought to include that extension if they're all like that.

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

I'm curious for those who have installed a Holley Sniper kit and have used the supplied Holley electric in-line fuel pump, is the electric pump noisy?

Thanks,
Miles

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

Sorry about the thread hijack Ekliptix but I figure this is useful info.
davepl, the throttle extension made a big difference for me. But Holley also has a progressive linkage available which you can adjust the snipers software for.
It reportedly makes a big difference.
Here’s the info on it.
https://forums.holley.com/showthread...I-WAAAY-Better

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

I'm not using the Holley pump, but a Tanks Inc module which has a factory style pump inside the tank. You can hear it a little.

Yesterday once the fuel got hot after 30 minutes or so of driving it was noticeably louder.

Much quieter in tank than the old Holley blue or black pmp hanging off the frame though!

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

Subbed

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

That looks really nice. Is one of them a bypass/return line? I'd think you would have some vapor lock issues with such a long run above a hot engine.

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

Yes, the passenger side port is the return line, so there's a constant high-speed flow of 60psi fuel past it at all times. When there's no draw from the engine, the pump is basically pumping full blast at all times circulating fuel, so it'll never sit in the lines.

It could over time heat up the fuel in the tank though! Now there's a 16' fuel line run that'll help cool it down but I might consider adding some insulation on the intake if I can make it kinda stock, thanks for the idea!

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

Subscribed. Planning on this for Walt, when I get the 468 swapped in.

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

Ahem .. practice on mine ? :lol:

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

Never even considered a return system such as this heating up the fuel in the tank. This could explain some hot start issues I've been having!

-klb

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

You buy it & I’ll come and help install it! ;). Sorry for the thread jack.

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

I hope to get it running again this weekend.

Cracked vs new
https://i.imgur.com/eYDjBlTh.jpg?1

Ready to install the new intake.
https://i.imgur.com/qHYifAWh.jpg

Torqued to spec
https://i.imgur.com/4hxMe4uh.jpg

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

I bet by now you can’t wait to get the truck out on the road.
Wise choice on the 4 hole spacer. I used an open one and had a very noticeable squeal on hard acceleration. I installed a 4 hole spacer and it’s totally gone.

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

For anyone following along, two things:

1) That "Notch" in the two-plane intake is important. If your intake is sealed all the way such that the two planes are totally separate, TBI EFI will not run well (or for some brands at all) because the MAP sensor is only on one of those sides. I can't tell if the old 4-hole was separate side to side, but the new one looks OK. The ZZ502 intake from Chevrolet has a notch too, but smaller.

2) Holley offers a linkage extension as well as progressive conversion linkage. I have ordered the progressive kit because otherwise it is VERY touchy. Consider that it opens all four barrels right off the start...

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

Interesting that progressive is an optional item.

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

Yes, it really should have been that way originally I think, or come with it. Having the throttle open ALL FOUR blades IMMEDIATELY as it does in stock form makes for a very sensitive throttle!

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

Davepl,

Where did you buy the throttle extension and progressive linkage for the Sniper? Can you provide part numbers?

Thanks,
Miles

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

Try this link for the Progressive, https://www.efisystempro.com/sniper/...ve-linkage-kit,


I was gonna purchase the fixed, price 13.18 but after seeing shipping to Canada costs 43.10 I might as well get one made here at a gold jewelry shop hehe

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

Thanks for the info!

Miles