Installing Holley’s Lo-Ram Manifold on a Fourth-Gen F-Body
By Wes Dunkel – Photography by the Author
General Motors’ fourth-gen F-body was a radical design. With its steeply raked windshield and bird-beak nose, the groundbreaking LS1 powerplant was tucked halfway under the cowl. Function clearly followed form at GM headquarters.
Here’s our test subject: a ’98 Camaro with a 370ci LS1 fed by two turbochargers. The mill made 797 hp on 19 psi of boost with the stock LS1 plastic manifold. The folks at Boost Addicts noted that the manifold would swell under full boost.
But with the LS1’s factory intake manifold nestled neatly in the valley of the Gen III V-8, cowl clearance isn’t a problem. However, intake manifold options are severely limited to low-profile designs. Those with high-horsepower engines had two choices: one, use the stock or aftermarket low-profile plastic intake manifolds; or two, cut the stock cowl, lose the windshield wipers, and possibly even cut the windshield.
Here’s the problem: the low cowl on ’93-02 GM F-bodies eliminates most aftermarket “ram”-style intake manifolds—unless you want to cut the cowl, lose the windshield wiper mechanism, and cut the windshield, and we don’t think that’s the best option.
Fortunately, Holley has an option: the Modular Lo-Ram EFI intake manifold for LS1/2/6. Its large, short runners are great for making big top-end power, and its large plenum complements supercharged and turbocharged applications. If the factory-style intake manifold on your cathedral-port LS engine is choking its potential, the Holley Lo-Ram EFI intake manifold is the ticket.
Same can be said for C5 and C6 Corvettes. See how this race Vette’s cowl is cut and the windshield wipers are removed to clear the Holley Hi-Ram manifold.
This thing is designed to flow some serious air. The Holley Lo-Ram EFI intake manifold (PN 300-621) accepts Holley’s monstrous 105mm throttle body (PN 112-581) to guarantee your engine gets all the air it wants. The front-feed design is a direct replacement for factory-style intakes, and its overall height is the same as that of a factory LS1 manifold.
The modular design of the Holley Lo-Ram EFI intake manifold utilizes a front-feed throttle body inlet and a removable cover.
The cast-aluminum construction is perfect for high-boost applications where plastic manifolds puff up like a balloon. There are even bosses for additional fuel injectors or nitrous nozzles.
The back of the Lo-Ram intake is plumbed for vacuum fittings and a MAP sensor.
Holley even includes a new set of fuel rails and two sets of mounting brackets: a set for long (usually standard length) fuel injectors and a set for short (such as Pico, or LS7) fuel injectors. Holley doesn’t leave you to “figure out the details” because they’ve already thought of it!
The short, fat runners are designed to maximize top-end power and mate to cathedral-port heads.
To sample the benefits of the Holley Lo-Ram intake manifold, we went over to Boost Addicts in Gallatin, Tennessee, to install one on a customer’s twin-turbocharged ’98 Camaro. Shoving 19 psi of boost through a stock, plastic LS1 manifold, this Camaro was the perfect candidate to show what the Holley Lo-Ram could do.
Holley gave the Lo-Ram room to grow, with additional bosses for dual injectors or nitrous nozzles.
Follow along on the installation details and some very interesting dyno results. ACP
After we were done ogling the Holley Lo-Ram, we removed the stock plastic LS1 intake from the engine.Then, we started assembling the Holley Lo-Ram intake by laying the supplied rope gasket in the top cover O-ring groove.With the cover in place, we installed the 12-point bolts.Then, we turned our attention to the front throttle body adapter. We routed the shorter rope gasket into the groove and marked where the two ends overlapped.With the top cover aligned and tightened down, we used a razor blade to trim off the excess rope gasket until it was flush.We used a razor blade to cut the rope gasket to the appropriate length.Cyanoacrylate (aka super glue) joined the two ends of the rope gasket.With the rope gasket in place, we installed the throttle body adapter bolts.Before installing the Lo-Ram, we compared it to the stock LS1 intake manifold. The Lo-Ram wins on looks alone. Note that we paired the Lo-Ram intake with Holley’s 105mm throttle body.Surprisingly, the Holley Lo-Ram intake manifold is the same height as the stock LS1 manifold. (The angle of this photo is a little deceiving: the Lo-Ram would’ve disappeared behind the stocker had we crouched lower.)Before installing the port flange seals, we laid the manifold on the head surface and checked for anything that would prevent the manifold from sealing.When everything checked out, we installed the included port flange seals flange seals.We plumbed the ports at the back of the manifold for the brake booster, boost reference, and crankcase vent.After using the included studs to fasten down the manifold, we prepped and installed the included fuel rails. These are billet aluminum jewelry. Note that we used the supplied “long” fuel rail brackets to accommodate these “long-style” fuel injectors.On looks alone, the Holley Lo-Ram means business. It fits the persona of this twin-turbo Camaro perfectly.We didn’t encounter any fitment issues. Even the throttle body was in the same location as the factory inlet. All it took was a larger silicone coupling to adapt the charge side tube to the Holley 105mm throttle body.Room to spare! The Holley Lo-Ram wasn’t any higher than the stock LS1 manifold.With the Camaro back on the dyno at Boost Addicts, we were ready to make some pulls.Even with dramatically shorter runners than the stock manifold, the Holley Lo-Ram made more horsepower and torque across the board. Peak gains were 44 hp and 26 lb-ft of torque.
