By FordMuscle staff.

Several months ago we embarked on a very cool project - converting our Project '67 Mustang from carburetion to fuel injection. Putting modern electronic engine control under a vintage shell is on the wish list for many enthusiasts and we were excited to show you how to do it. In Part I of DIY EFI we detailed all of the steps involved in getting the wiring, hardware and fuel system selected and installed. We used Mass-Flo's Ford EEC-IV based kit which simplified procuring and installing the various required parts. The real plus to the Mass-Flo kit is their under-the-air cleaner mass air meter which maintains a carbureted look. We also liked the idea of using a modified single-plane carbureted intake manifold (we used the Edelbrock Victor Jr.) This would allow the high-rpm capability we desired and make for an interesting power comparison between carburetion and fuel injection.

The degree of difficulty for converting a carbureted car to EFI is not terribly high, however there is plenty of time spent in planning for things like the fuel system and then properly installing all of the components. This is especially true if you are planning for significant power upgrades. In the case of Project '67 the decision to convert to EFI came after repeated struggles trying to tune the carburetor for the blow-thru supercharged 331cid engine. We had conceded that we were likely go broke repeatedly paying for custom carburetor modifications to provide us with a safe air-fuel ratio for the 8psi of boost and 10.8:1 compression ratio. We rationalized that the up front expense for an EFI conversion would pay dividends in virtually limitless tuneability.

Our EFI conversion kit is by Mass-Flo. It's based on the Ford EEC-IV system however the throttle body and mass air meter are purposely designed by Mass-Flo to fit a carbed single plane manifold (modified for injectors) and conceal under the air filter housing for a sleeper look.	The Mass-Flo kit includes a custom EFI wiring harness in the correct length for your vehicle and stripped of the various emissions sensors that are not necessary for engine operation. We mounted the processor and fuse block under the passenger side dash.
Since we are running 331 cubic inches and a big cam, Mass-Flo burned a custom tune for our A9L computer. It simply fits into the service port on the back of the A9L. Mass-Flo adjusts the parameters for the larger displacement and 30lb/hr fuel injectors and mass air meter.	The fuel system consists of an inline high-pressure EFI fuel pump to feed the 30lb/hr injectors, a regulator and return line. With the engine running we adjusted the fuel pressure to 39psi. It is important to make all fuel pressure adjustment with the vacuum line to the regulator disconnected. Pressure will drop corresponding to manifold vacuum once the line is reconnected.

So the initial plan was to get the engine converted to fuel-injection and have it running naturally aspirated. Once we got it optimized and dyno tested to compare against the carbureted setup we're reinstall the blower and step-up in injector and mass air size. Since the car would be down during the conversion we also used the opportunity to install the set of Dart Pro-1 CNC cylinder heads we had featured some time ago. This would also allow us to drop the compression ratio one full point and install a set of Cometic multi-layer steel (MLS) head gaskets to hold in the boost. We concluded Part I with having all of the hardware, fuel and electrical work completed. All that was left was to have the exhaust reconnected and setup for oxygen sensors.

We also installed a set of Dart Pro-1 CNC cylinder heads while the car was down for the EFI conversion. Take note of the spark plug angle in relation to header bolt. We'll comment on this later in the article.

We had our local exhaust shop reconnect the exhaust and weld in oxygen sensor fittings. We also placed an extra fitting so we can use our Innovate LM1 wideband for tuning and monitoring air-fuel ratio.