I thought I would share my “cost effective” fully sequential fuel and spark EFI conversion with everyone. I know I’m not the first one to convert an LA Mopar to EFI, but I haven’t been able to find a comprehensive thread on this specific topic, so I figured it would be nice to have all the information in one spot for anyone looking to make the switch. I want to preface with a few details. · I call this cost effective because in no way did I try to find the absolute cheapest way to do this, nor did I go at it with an endless budget. It can certainly be done for much less money, but my plan was to build a nice, reliable EFI system without spending $5K on something that still required modification to suit my needs. · I’m no expert, I learned as I went through this using knowledge from books and online success stories. If I say something you disagree with, I’m happy to listen. · I’ll list some prices that I remember, but some may have changed since I purchased them. Let’s get started. The basis of my build is a 408ci, with aluminum heads, and solid roller cam. I used this same engine for drag racing my car and it was pretty stout running 10.50s in an all steel car. Once I decided to quit racing and put the car back on the street, I detuned the motor by replacing the pistons (lower compression) and a much milder, 112 centerline cam. I had planned on using speed density EFI control, which means the engine needs to produce a vacuum signal. The old 106 centerline cam wouldn’t cut it, nor was it good on the street. After I educated myself enough, I started deciding on and procuring parts. I’ll separate all major parts in separate sections to make details easier to find. Intake Manifold Since I already had a Mopar M1 single plane intake, I decided to use that intake and have injector bungs welded into it. I sourced the bungs from ebay (approx. $30). I also sourced some Edelbrock EFI rails so my machinist would be able to get the spacing correct. The rails are designed for the Magnum motors and were about $100 at the time. Edelbrock also makes an intake manifold with the bungs casted into it. I think it is about $350. Throttle body Initially, I wanted to use a single, forward facing, LS style 92mm throttle body. I purchased a used one on ebay, along with an Edelbrock throttle body elbow. I like the look of this setup, but ultimately it wouldn’t work with an A/C compressor unless it was turned sideways. That ended up not being the look I was after either. So I sourced a 4 barrel throttle body off ebay. It was $159. There are tons of name brand 4 barrel throttle bodies out there. It’s absolutely absurd what these companies what for that product. I think the next lowest cost from the one I bought is $500. That’s plain stupid. It’s a chunk of aluminum with some throttle plates. I don’t get it. ECU I used the Megasquirt MS3X. I actually bought the kit and built the controller myself. This saves you a few bucks, but you will need to be pretty good at soldering small components. They have options to purchase them already built and even have new and improved ECUs with better connectors and a few more features. I may upgrade to that one day. Check out diyautotune.com for details and prices. Megasquirt gets a bad name in some respect since it is basically an open source product. They have gotten better over the years with support, but since every application is different, their tech support may not be as good as Holley since they sell cookie cutter systems. Megasquirt uses Tunerstudio for configurations. There is a free version, but for $60 all of the features are unlocked. It’s worth the money, get it. Sensors- Once you decide what sensors you are going to use, go to a junk yard and get a few sensors of the same type along with their connectors for when you are building your harness. · Fuel injectors – used take offs from an SRT-8 Hemi sourced from ebay. Find an online calculator to determine what size you will need for your motor. Be honest with yourself here. You don’t want to put that your engine makes 600HP if it really only makes 250HP. If you get injectors that are too big, idle tuning may be difficult. · Water temp- GM style, nothing fancy. Get them off a junkyard engine, or diyautotune sells them with the connectors. · Intake air temp- GM style, same as above, but I used something different. I’ll get to that further down. · MAP- most GM MAP sensors work, but I used something special for my setup, more soon. · TPS – The 4 barrel throttle body uses a TPS from an early 2000s Ford. I looked at a bunch of different ones at the JY and they all looked the same. I grabbed a few of them. The single 92mm throttle body uses pretty much any GM style TPS. · IAC – GM style I did learn there are two types, one with a brass cone shape valve tip and one with a rubber tip. The 4 barrel throttle body needs the one with the rubber tip. I believe it came on an early 2000s GM. Look on rock auto through the GM products. They have pics of the product on their site, which is helpful. · Crank position- I used a threaded body sensor from DIYautotune with their 36-1 trigger wheel. I had the hole in the trigger wheel bored to match the backside of the steel crank pulley, then put a couple tacks to hold it in place. Once installed on the engine, I drilled and pinned it to the damper so I can put it back into the same position if I ever have to remove it. · Cam position – The sensor is a 2004ish Jeep 4.0 cam position sensor. You will want to get this whole piece out the junkyard. You can get it all new, but why? I did end up buying a new sensor, but the drive piece is required. You will also need the adapter for this. SD Concepts sells them. I paid like $50 for it, but I think he has raised his price now. He also offers a complete kit for this now. · Coils – LS D585 coils. I think these come on 6.0 GM trucks or suburbans. They are the ones with the heat sink on the top. I read these were better, I don’t know why. They were the same price at the junk yard as the standard ones so I got them. Make sure to grab all the connectors when you get these. · TMAP- OK, this is what I used on the throttle body. It’s a MAP sensor and inlet air temp sensor in one. I loved the idea of combining the two for a more sanitary installation. I haven’t figured out what car they come on, I found them on a random website that sells sensors. I think it has a Bosch number on it. I’m sure I could take it to a parts store and have them cross it over. Fuel tank/pump/regulator If you haven’t heard of Tanks Inc. maybe you are living under a rock. The manufacture tanks for many makes and models and also offer EFI conversion tanks. Their tanks use a drop in style pump hat and the tank is baffled to keep the fuel around the pump. I used their pump (size according to your HP needs) and I also used the “corvette style” filter/regulator. This basically allows you to use your existing fuel line without having to run a return from the engine back to the tank. I’ve heard good and bad about these, but I haven’t had a problem yet. Wiring Harness You will have to build your own engine harness since no one makes a drop on harness for the LA Mopar engine- at least I don’t know of anyone that does. DIYautotune sells harnesses with one open end (it has the ECU connector on the other end) Get one of these. They have wiring diagrams on their website for basic wiring. I was able to find all the diagrams I needed to get started. I realize this is likely the most confusing part to some people, and I’m happy to answer any questions.