Since the throttle body is designed to replace any carburetor that works on a 4150 square flange manifold, it was a "no brainer" for FAST to make the unit accept any Holley-style throttle linkage. Just like a carb, you'll want to make sure to use a throttle return spring or two. Also, just below the braided crossover fuel line is the TPS Idle re-calibration screw.

On the passenger side of the unit you'll find the air temp sensor and the throttle position sensor.

Meet the brains of the system: the ECU. When connected to the wiring harness, the ECU is water tight, and can be mounted just about anywhere. FAST recommends that the ECU be mounted at least a couple of feet away from any "noisy" components such as ignition boxes, coils, or distributors. There's also a red LED near the logo that will flash if the ECU detects a problem.

Also included in the kit is a wideband oxygen sensor, and a bung for the exhaust system. The fitting needs to be welded, but if you can't do it yourself, any competent exhaust shop can install it for few bucks. Run the supplied plug in the hole until you have the system installed and not the sensor itself. Running the O2 sensor without it being connected will shorten its life due to deposits building up.

The wiring harness may look like a bowl of spaghetti, but it's surprisingly easy to install. One reason is that all the connectors are clearly labeled, and FAST includes several wiring diagrams to make installation a snap.

One sensor not integrated into the throttle body is the coolant temperature sensor. It can go just about anywhere, but we chose to mount it in the intake manifold using the supplied adapter.

And with that, the system was installed and we were ready to fire up the 454 to start the calibration process. In regards to fuel, our Superflow 902 dyno already has an EFI-ready system. If you're converting from a carb, you will need an electric pump and regulator capable of putting out 43 psi. To make things easier, FAST does offer a fuel pump and a line kit just for the EZ-EFI system.

Setup and tuning of the EZ-EFI is done through this handheld interface. It has a straightforward menu system that we found very easy to negotiate. In addition to setting up the system, it also serves as a scan tool that displays live data and diagnostic information.

The first step was to fire up the engine and let it warm up to the target temperature of 140-plus degrees. During this process, we adjusted the throttle to maintain idle. We also had to input the engine size, fuel pressure, and a few other pieces of information. This was all done in a step-by-step process using the menu's setup wizard function. From the main menu, you can track live data, read error codes, and perform advanced functions.

Under the Advanced Options screen, we set our target idle speed, rev limiter, and put in our air/fuel ratio targets. The rev limiter works by disabling the fuel injectors until the rpm drops to a safe level. According to FAST, this can also be used as a form of "valet mode" since it's easy to temporarily lower the rpm level.

For our application, the guys at Westech went with 14:1 at idle, 13.8:1 at cruise, and 12.8:1 at wide open throttle (WOT). During the course of the day these were adjusted a bit since it takes some experimenting to find just the right setting. For example, when cruising, a leaner target (higher number) will use less fuel and increase mileage, just remember not to let the system go too lean.

The key to the FAST EZ-EFI system is its adaptive learning feature. This system goes beyond normal closed loop fuel control. In essence, it tunes itself by using oxygen sensor feedback to adjust the underlying base fuel table as well as the instantaneous fueling. This way the closed loop system only has to make fine adjustments. We found that the system took a while to learn, and the more we ran the engine, the better it did. If installed in a car, the best tactic would be to get the engine idling good and then drive around for an hour or so.

We decided to make our first baseline pulls using a 750 CFM Holley carb. Given that the EZ-EFI system is rated up to 550 hp, this seemed like a carb size it would replace. The best pull we got with the carb was 526 lb-ft at 3,900 rpm and 504 hp at 5,700 rpm.

Here you can see one of our better EFI pulls compared to the earlier carb numbers. The FAST system made 532 lb-ft at 3,800 rpm, and 496 hp at 5,600 rpm. In essence, it lost eight peak horsepower to the carb, but made an additional six pounds of twist. I guess we would call that a draw between the two. Where the EFI system excels though is drivability. Where we had to crank to start the engine with the carb, the same engine with the EFI system started with a push of a button.

Purely out of curiosity, we decided to also try a bigger carb on the engine. In this case, the 1,000 cfm Holley HP that was on the engine when we bolted it to the dyno. It put down 531 lb-ft at 3,900 rpm and 516 hp at 5,600 rpm; about the same torque as the EFI system, but 20 more peak horsepower. The down side would be that the 1,000 cfm carb sucks fuel like it's going out of style compared to the EZ-EFI. There's also a chance that over time, with more WOT driving, the adaptive learning function would further fine-tune the EFI system and raise our peak numbers a bit, but most likely not up to the numbers put down by the monster Holley carb. But, for a street car that spends most of its life under 5,000 rpm the EZ-EFI system offers performance on par with a traditional carb with drivability that the carburetor can't come close to. Best of all, it really was easy to install.