EFI considerations for a 1970 383 with very mid cam

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Duster_Dean

Duster_Dean

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Hello all,
I am switching from an Edelbrock 650 to an efi.
Looking for some key considerations I need to be aware of when picking the efi system.
This is my first swap so any knowledge is better than whee I am now.

I have a new tank, inside tank fuel pump and feed / return lines - just need the efi.
Switching for easier starts and more reliability.

TIA
Dean
 
Last year I installed the Gen 1 Sniper and am now driving it more and I love it. Easy start, faster warm up, will high idle without fuss, Cruises easy and goes like hell. I did the entire system, Hyperspark distributor, ignition box, fuel pump (you don't need a return with their pump), etc. The Gen 2 stuff looks even easier. I will say there is a lot of support for the Sniper as is their other EFI systems. I'm not a Holley fan boy but a friend of mine has installed over 8 of these over the last 6 years with perfect results.

Regardless of what you pick be sure you have good new grounds from the block to the frame, frame to battery, and battery to frame. Also, a higher amp alternator and all the supporting mods to not burn up your harness.

It is nice to have the car sit for a few weeks and go out and turn the key and have it fire in 5 seconds (most of that being the time to prime) and back it right out of the garage and drive down the road cold.
 
I love my Holley Sniper, however I could never get the Hyperspark distributor and matching coil unit to work without back firing so I'm running it with my old pertronix distributer and accell coil. It runs great, starts great when cold, but does suffer from hard restart if I shut it off and try to immediately restart the engine when it's hot.
 
Another vote for sniper. Heed their warnings for keeping the sniper wires (to sensors and such) away from ignition wires as well! I run mine with MSD distributor locked out and 6AL box.

Also agree with the instant restart difficulty. I think it’s just a little too much fuel, gets the plugs wet. You can usually get around it by holding the pedal to the floor to prevent the fuel priming.

Read up on the AE vs throttle position change parameters, will give amazing throttle response!

The MSD Atomic I ran previously ran great too, switched to the dual quad sniper setup.

A buddy of mine is going to multi port with super charger and is selling his used sniper setup. You can PM me for his contact info if interested.
 
The Sniper is probably your best bet. They have a lot of support and they generally work pretty well but they aren't perfect. I highly recommend buying from Summit rather than direct from Holley. Summit will exchange the Sniper if there is a problem but Holley won't. I also highly recommend a matching Hyperspark distributor. You can use an MSD box and coil if you already have one. You just need a box that has a "points in" wire so you can send the signal to the ignition box from the Sniper. If you don't have an ignition box then the Hyperspark box is okay, or use the MSD 6EFI.
 
Thanks to all for the information, experience and recommendations.
My prelimanary reseach showed the Holley as a very good candidate.
Another question:
I currently have an MSD distributor and MSD 6AL box. It's hard to tell from your posts if this is suitable with a Holley Sniper.
Will this be ok or would I need to change out these components?
I see I forgot to mention the motor is a 1970 383 out of a Road runner.

Thanks again
 
The MSD 6AL will work fine with a Sniper and so will the coil that you are using. The MSD distributor won't work so send it to the swap meet and budget for a Hyperspark distributor.
 
I've been reading a LOT about the Sniper2 and it sure sounds good. 4 wires to hook up and that's it. Has good reviews, too.
 
I installed a Sniper 1 full system (Hyperspark ignition and a Mopar fuel sender with the pump and return built into it) last year on a '72 Duster with a 360 and could not have been happier. I expected nothing more than easier starts and smoother running, but I got way more. Love the self-learning feature and being able to fine tune it myself from there. It really gave the 360 a kick in the shorts. The only issue I had with the installation was pretty bad EMI that I needed to mitigate with ferrite beads on all of the wiring runs to shield it and get the ECU to operate correctly, but it sounds like Sniper 2 has addressed that issue. Highly recommend.
 
When does an aggressive camshaft become an issue with the Sniper?

Running 440 with 241/247 duration at .050, 545 lift both, and 110 LSA
 
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RustyRatRod said:
I've been reading a LOT about the Sniper2 and it sure sounds good. 4 wires to hook up and that's it. Has good reviews, too.
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On an old Mopar it is much more difficult than just 4 wires to hook up. Anyone who is thinking of buying a Sniper should spend a few hours reading the Sniper forum on the Holley website. The Sniper is a great product, but they are difficult to install for a lot of people. People who can't figure out how to attach a picture to an email will have problems with a Sniper. Same with people who think twisting wires together is a good connection.
The problem with a Sniper on an old Mopar is that old Mopars used IGN 1 and IGN 2 for run and start circuits. Those two circuits need to be tied together to power a Sniper. About 50% of the Mopar guys who try to install a Sniper get stuck at this point. The other 45% get stuck trying to figure out what to do with the ballast resistor. The various forums are full of these two questions. The other issue is that only the most popular cars have drop in fuel pump modules. If you don't have a popular body style then you end up having to hack the fuel system which isn't any fun.
I did a Mopar install article for Car Craft back in 2018 when the Sniper first came out and I've done a bunch of other articles and videos since then but people still have problems with the installs.
https://www.motortrend.com/articles/super-sniper-efi-sees-powerful-improvements-data-logging/
 
AndyF said:
The problem with a Sniper on an old Mopar is that old Mopars used IGN 1 and IGN 2 for run and start circuits. Those two circuits need to be tied together to power a Sniper. About 50% of the Mopar guys who try to install a Sniper get stuck at this point.
Click to expand...

So the Sniper doesn't have an issue with the loss of connection when the key comes off start and back to run? For a microsecond, there isn't juice on either circuit and it messes with the G3 swaps and causes the PCM to think the car turned off so it won't keep the motor running. So the Sniper isn't as sensitive maybe?
 
When I did my install I used Holley's off the shelf harness 558-328 and the only factory wiring used is the IGN1 and ING2 tired as referenced by Andy. Keep in mind this is for the Gen 1 system with Hyperspark ign box and distributor. It's over priced and kind of oddly laid out but I made it work about as clean as I could with out cutting.

To me, the confusion comes with the 4 install manuals you need to mentally patch together for the install plus the things they don't tell you and you learn from forum searches.

The Gen2 system looks to be a massive clean up and more "system" oriented.

It is a challenge at times, but tuning is so much nicer. No more gas, jets, pump cams, springs, distributor curve chasing and you can data log.
 
DionR said:
So the Sniper doesn't have an issue with the loss of connection when the key comes off start and back to run? For a microsecond, there isn't juice on either circuit and it messes with the G3 swaps and causes the PCM to think the car turned off so it won't keep the motor running. So the Sniper isn't as sensitive maybe?
Click to expand...
I got around this limitation when I installed my Sniper 1 by using a time delay relay. I built a simple circuit to keep the start signal hot for a brief period of time while transitioning from START to RUN. This worked fine, but was a little weird because I never took the time to "dial in" the delay time, so the car runs for a second or two after you turn the key off. I got used to it and it never bothered me enough to play with the delay settings on the relay, but I'm sure it could have been timed to make it unnoticeable.
 
67fish383S said:
I got around this limitation when I installed my Sniper 1 by using a time delay relay. I built a simple circuit to keep the start signal hot for a brief period of time while transitioning from START to RUN. This worked fine, but was a little weird because I never took the time to "dial in" the delay time, so the car runs for a second or two after you turn the key off. I got used to it and it never bothered me enough to play with the delay settings on the relay, but I'm sure it could have been timed to make it unnoticeable.
Click to expand...

Makes sense. The default fix for a G3 swap is to wire in a start button and only use the run position on the key.

My plan is to use an F-Body ignition switch. It bolts in and has a circuit that is powered in both run and start, but it's far from a drop in fix.
 
I'll be the odd man out here and toss one in the hat for FiTech. I've been running mine issue free since the day they came out about 8 years ago. I have read many horror stories about them, which most are installer error. The Sniper does seem to have a little more tunability available in it, the FiTech table is only 3x3.

As far as cam size goes, mine runs good on a 252 duration @ 050 on a 112. It just like with the carb, under ~2200 would load up a bit.
 
DionR said:
So the Sniper doesn't have an issue with the loss of connection when the key comes off start and back to run? For a microsecond, there isn't juice on either circuit and it messes with the G3 swaps and causes the PCM to think the car turned off so it won't keep the motor running. So the Sniper isn't as sensitive maybe?
Click to expand...
I've never seen an issue with that. I've had a Sniper in my car for 8 years now and I've installed dozens of Snipers on other cars. Maybe there is a capacitor on the input line that provides a little bit of "smoothing" so the ECU sees enough voltage to stay turned on.
 
It's possible to get around the two IGN terminal issue by using a relay with a capacitor across it's coil, making it close slowly enough to stay on while switching terminals.

But let's back up a little: What are your goals and priorities for the system? Are you trying to get a little more drivability on a budget? Add features that will help you win drag races or autocross? Tune for forced induction? Drop jaws at the local cruise night? The TBI setups discussed can make sense for the first goal, but some of the others might call for a Dominator, Haltech, MS3, or other choices.
 
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