Mild 440 (basically a stock 440 Magnum), dual plane intake (no option here unless there's a single plane the same height as the factory iron), and iron manifolds. What's the best out there for this setup? My son is willing to spend the money for the distributor and all that it takes to work best. He's looking for turn key reliability and good performance.

Holley Sniper. I have installed a few different brands and they are the best for the money. I have never had any issues with running them on dual plane intakes. The Hyperspark ignition is nice, but not necessary if you want to save some coin.

You can get a factory reconditioned Sniper for $799. That is what I'd recommend for your engine. If it was me I'd add the Hyperspark so you can control engine timing and if Tanks Inc. makes a drop in EFI gas tank I'd install that too.

https://www.holley.com/products/fue...refurbished_-_sniper_efi/parts/FR550-511

Yes, we are going with a Tanks Inc. tank. His tank and pickup were in bad shape when I pulled them out last year so he needs a new tank anyway. That's a great deal from Holley vs. Summit's price. Might try to get all the parts that they sell from them.

I don't have any experience with the throttle body EFI systems but if I were to buy one right now It would be the holley sniper. I follow lots of EFI stuff and for that application that is what I would do for sure. I would stay away from Fitech.

A friend of mine has a shop that has installed a few of the MSD Atomic EFI systems and they have had great luck with them as well.

I've installed/tune a FiTech and will be trying out a Sniper for my own truck. FiTech does work out great, but the controller and user interface leaves a lot to be desired.

Another vote for the Sniper. Been on my car for two years now on a 512 and it's been great.

I've been looking at the Edelbrock RB injection set ups
If I still had a MOPAR street anything I would be going this route.

I have a neighbor friend that has the MSD Atomic on an LS in his Chevelle. while it works fine, getting tech support for it has been a challenge. I guess there is a group that he belongs to on Facebook and they have managed to figure out most of the issues on their own. He really wants to switch over to Holley.

Holley has owned MSD for awhile but I imagine the support is better for the products under the Holley name.

I to have done some MSD Atomic, very basic system, works great, IF I was to do a T body EFI it would be the Holley Terminator Stealth

I was looking at that at one time also. I wonder what is limiting power to 550hp?
Injector size, throttle size, plenum size, runner length, volume, cross section?
All of the above? Could it be as simple as just needing bigger injectors?

I went out and read reviews of the Holley Sniper 4-bbl and no one was happy with it. I have a friend with a FiTech and it turned out great but as previously mentioned, the interface and owner's manual leaves much to be desired. His is on a Ford FE and it took four (yes, four) hours on the phone with tech support to get it to work properly.

Your son will be happy with the Sniper as long as he has a basic understanding of computers. You need to know how to move around in a file system to find files, copy files, load files, etc. If your son has a laptop computer then he will be super happy with the Sniper. He can buy an interface cable and hook up his laptop to the Sniper and super tune it. Can even tune it while driving down the freeway. The Sniper contains a very advanced EFI system but you have to buy the special cable to access it. The Super Snipers come with the cable but they cost more. For your car I'd buy the reconditioned unit then add the cable later if your son wants to hook up a laptop to access the other features.

Yes bigger injectors HP to 800ish...thats what they told me back in June.

I recently put a sniper xflow on my Satellite. Install went well. Only got to drive it once on Dec. 13th. before they began salting the roads around here. Locked the trusty old mopar perf. distributor and set it up to control timing too. So far so good. Gonna have to wait for spring to do much more with it.

Yes you can order the Edelbrock unit with the larger injectors to handle more power. The Edelbrock systems that I've used work okay but they are a black box. They don't have any data logging capability and you can't make many adjustments to the tune. If they work then great, if not then there isn't anything you can do about it.

The success is heavily dependent on your ability to either A) Understand how EFI works B) Your desire to know about how EFI works. The systems are sold as "plug it in, fire it up and go". While they're quite good, they require tuning if you want it to drive like a new-ish car.

Understanding of IAC operation, how coolant temp effects fueling, rotor/timing phasing, acceleration enrichment, RFI/noise suppression, cold start enrichment, warm-up enrichment, etc. are all going to be necessary skills to execute the swap well. YouTube is loaded with helpful videos on this stuff, but one has to want to learn how to do it. A large portion of the TBI kit buyers simply don't want to do that.

My Father in Law is who I installed the FiTech kit for, he has pretty good carb knowledge but was initially clueless on EFI. Without someone knowing EFI around [me], I can see the process for him being very frustrating, which is where many people who write reviews online find themselves. That said, his truck has never ran better!

Yes, I see this every day of the week on the Sniper forum. The people who are unhappy with EFI are typically people who don't have good computer skills. They don't understand how to debug computer issues so they get frustrated. I worked with a car builder a while back who was super frustrated with an EFI system. This guy has been building high quality street rods for 40 years but he didn't know how to find a file on a hard drive so he couldn't upgrade his firmware. The guy knows how to fabricate any part on a chassis but he was stumped when it came to upgrading the firmware on his EFI system. I went over there and it took me less than 30 seconds to find the file and do the upgrade. So there isn't anything wrong with the EFI systems, but there are a lot of hot rodders who haven't yet learned how to install, tune or debug them.

Another thing I see a lot of is that when hot rodders put EFI on their car they then blame the EFI system for anything that goes wrong. I got called out to a local hot rod shop last week to help them get a EFI conversion sorted out. They were all upset that the Sniper was not working and asked me for some help. I show up and after fiddling around for a while I see that the throttle body wasn't bolted tight so they had a vacuum leak which was causing an issue with the idle speed. They fixed that and then I noticed that the throttle linkage wasn't properly adjusted so the throttle body wasn't getting full throttle. That was why the engine didn't have very much power. They also had the system wired wrong and they had a leak in the fuel line. There was nothing wrong with the EFI system, it was just a bunch of mechanical problems. Had they had a carb on there they would've found all those issues. Since it was EFI they just assumed that the EFI unit was bad. These are guys who have been building hot rods for 50+ years. They have build hundreds of cars so they know what they are doing but they weren't familiar with EFI so they just assumed it was causing all of the issues.