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Installing Edelbrock’s Performer Truck 5.0 Intake And BBK’s Twin Power Plus Series Throttle Body On A 5.0L 1991 Bronco

Posted in How To: Engine on October 5, 2016
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Ford truck engines back in the late ’80s through the mid-’90s were pretty sorry performers compared to today’s offerings, but they were competitive at the time. Base model F-150s and Broncos came stock with a 150hp 4.9L (300ci) I-6 through 1993, while Eddie Bauer editions came with the 185hp 5.0L (302ci) V-8. Those with a penchant for more horsepower opted for the 210hp 5.8L (351ci) V-8. By the end of Bronco production in 1996 the 302 was cranking out 205 ponies, only 5 hp behind the 351. We laugh at those numbers today.

Despite the low horsepower output, those early EFI Ford V-8s are good engines. They just couldn’t breathe well. That’s why Edelbrock came out with a 50-state-legal, direct replacement Performer Truck intakes for EGR-equipped 5.0L/5.8L EFI engines, which are claimed to add 35 hp on the top-end with a considerable gain in mid-range torque over the stock setup.

Getting that kind of bolt-on power boost from the stock 5.0L in our ’91 Bronco piqued our interest, as did the idea of replacing the stock 56mm twin-bore throttle body with BBK’s twin 61mm Power Plus Series throttle body, which could bring another 10 hp to the performance table.

Perfect Performance Pair

Edelbrock gets those power gains with a modular-designed CNC-port-matched aluminum upper and lower intake. The lower manifold is taller and its ports are rectangular instead of having the odd semi-curved shape of the factory intake. Those aspects, combined with porting to match the upper manifold, creates a considerable increase in airflow through the longer, equal-length Edelbrock runners.

The Edelbrock Performer Truck 5.0/5.8L EFI plenum is also larger with additional porting into the long runners. The design and machining of the two-part intake is all part of Edelbrock’s latest airflow design and CAD technology, which helps feed considerably more air into the heads than the stock intake. More air means the 5.0/5.8L can breathe a whole lot easier, which means more fuel can be added for more power. What’s nice about this bolt-on performance upgrade is the two-piece Performer Truck intake is a straight swap for the stock system, including all the components to keep the engine 50-state compliant for those who have to pass emissions testing.

The same is true for BBK’s twin 61mm Power Plus Series throttle body, which is CNC-machined from a 356 aluminum casting. The high-flow throttle body is built with double-sealed bearings, an O-ringed throttle shaft, and die-stamped throttle linkage so it exceeds OEM quality as the airflow gatekeeper for the intake. BBK’s throttle body is a bolt-for-bolt, smog-legal replacement for the stock unit, and it’s a perfect performance companion for the Edelbrock intake upgrade on an F-150/Bronco 5.0/5.8L engine.

Making The Power Swap

Swapping out throttle bodies on an older Ford truck EFI takes about 30 minutes. Changing the intake takes the better part of a day. That was the scenario when we rolled a ’91 Bronco into Dunks Performance’s shop to have the mods done on its 5.0L engine.

What made the intake upgrade a real pain is these Fords had every smog-related hose, vacuum line, pipe, valve and switch known to man at the time attached to the engine, making it a mechanic’s nightmare. Once Dunk’s technician Scott Blanchard dug through the smog wiring and plumbing, the task at hand was the basic intake swap. Reassembly included new gaskets along with replacing almost every smog-related component on the 25-year-old engine.

When everything was back in place, we cranked up the engine, let it come up to operating temp, then turned it off. The Idle Air Bypass (IAB) connector was disconnected and the engine was restarted so the idle could be adjusted manually, all per BBK’s instructions. Then we plugged the IAB back in and went for a test drive.

The change in overall driving performance was quickly noticed. Our aged Eddie Bauer Bronco accelerated considerably stronger than it did before the Edelbrock/BBK upgrade with a slight whine from under the hood as the high-flow throttle body and intake sucked in volumes of fresh air. True to Edelbrock’s claims, the biggest performance boost seems to be in the 2,500-5,000 rpm range, where the added torque helps get the heavy Bronco rolling. It responds quicker to throttle too.

Looking to the future of this Bronco, we can imagine how sweet the Edelbrock/BBK combo would be if it were installed as part of a 5.0/5.8L rebuild running a mild cam and a freer-flowing performance exhaust system.

Edelbrock’s Performer Truck 5.0 intake kit for the ’87-’96 Ford 5.0L with EGR comes complete with everything needed for the installation. The port-matched, CNC-machined lower intake and upper plenum are said to add upwards of 35 hp. A version for the 5.8L/351W is also available.
Stock 5.0L V-8s of the era were heavily smothered with smog controls and a rather poorly designed EFI intake system. Our ’91 Bronco 5.0L engine was factory rated at a rather dismal 185 hp. The new intake and throttle body should raise that number to 225-230 hp. It took Scott Blanchard, one of the techs at Dunks Performance in Springfield, Oregon, the better part of a day to extract the old intake and put the Edelbrock/BBK system on our Bronco’s engine.
The OEM upper intake (top) has a smaller plenum and shorter intake runners than the Edelbrock Performer. Edelbrock’s runners are also port-matched to the lower intake and computer-designed to flow max air.
One trick Blanchard used when removing the OE manifold is to use pieces of colored wire to mark all the vacuum lines, hoses, injector plugs, and electrical connectors. Doing this will speed up the reinstallation process. When the upper EFI intake is off it’s a good time to inspect the injectors and any other hard-to-get-at fuel- and smog-related items that may need to be replaced.
We used a vacuum to suck out crud from around the lower intake before it was removed. We didn’t want any debris getting into the open ports on the heads.
Once we had the valley tidied-up and all the hoses, vacuum lines, and sensors disconnected, it was easy to remove the stock lower intake.
Edelbrock’s Performer Truck intake (near) is nearly 2 inches taller than the stock unit, providing greater airflow and a better air/fuel mixture into the heads. The Performer Truck manifold is a direct replacement for the OEM, and it’s 50-state smog legal.
Blanchard cleaned off the old intake gaskets and lightly smoothed the mating surfaces on the heads before applying a high-heat RTV sealant. The Edelbrock intake gasket kit fits 302/351ci engines from 1963-1996 and must be used when installing the Edelbrock intake. OEM Ford gaskets do not fit.
The aluminum Performer Truck lower intake kit came with new bolts and related gaskets. We also installed a new thermostat housing and 195-degree thermostat as the OE housing and thermostat in this truck were on their last leg.
During our replacement of old parts and sensors we found the OE intake air temperature sensor (right), located in the intake manifold, was at death’s door. We replaced it with a new one from Advance Auto Parts along with a water temperature sensor.
Installation of the upper intake (plenum) is fairly easy. However, before it was lifted into place, Blanchard installed a new air manifold (EGR) tube that runs from the EGR valve to the top of the lower intake where it attaches to a fitting directly under the upper runners. (You can’t get to the tube when the upper manifold is in place.) We also replaced the EGR valve.
BBK’s twin 61mm Power Plus Series throttle body is almost a piece of art. It’s machined from an aluminum casting and all the working parts are said to exceed Ford specs.
The big difference between the OE 56mm throttle body (left) and BBK’s 61mm Power Plus replacement is the size of the bore and the cleaner routing of the water circulated through the housing. The BBK throttle body can add up to 12 hp to the stock 5.0L.
Our Bronco already had an Airaid Poweraid throttle-body spacer installed, so we reused it when installing the larger BBK throttle body, hoping it would add a couple more horsepower and better mpg to the equation. We initially reused the original throttle position sensor that attaches to the bottom of the throttle body. Bad idea. It ended up being a problem shortly afterwards. Our recommendation: Put on a new one while it’s out in the open.
One item we almost overlooked in our Edelbrock/BBK upgrade was replacing the injector O-rings. When we pulled one bank of injectors out we found the O-rings to be brittle, and one came apart when it was pulled off. We replaced both sides as a part of the R&R.
Our Edelbrock/BBK intake upgrade on this ’91 Bronco’s 302 was done after spending the better part of a day in Dunks Performance’s shop. It looks great and made a big difference in how the 5.0L engine runs, especially in low- to mid-range rpm.

Sources

BBK Performance
Temecula, CA 92590
951-296-1771
www.bbkperformance.com
Edelbrock
Torrance, CA 90503
310-781-2222
www.edelbrock.com
Dunks Performance
541-726-1006
http://dunksperformance.com/

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