Ultimate Malibu LT1 Swap

Our 305 is gone but not forgotten...yet....        read full caption Our 305 is gone but not forgotten...yet. A couple of hours worth of degreasing and fogging with Eastwood’s Underhood and Chassis Black made a night and day difference to our engine bay.

Do the same to yours and save...        read full caption Do the same to yours and save yourself the embarrassment of explaining why you didn’t do it while the motor was out.

Our LT1 motor came out of...        read full caption Our LT1 motor came out of a fourth-gen F-body and used a 1-1/2-inch offset motor mount on the passenger side. The motor-mount boss (arrow) that used to hold our former 305 now holds the A/C compressor. Our only choices were to either notch the frame or to eliminate the A/C, which in itself would disturb the serpentine belt system. To alleviate the problem, we opted to remove the compressor and order S&P’s custom bracket kit and accessories. A Corvette LT1 bracket setup that places all the accessories on the driver side would have been a cheaper alternative, but can be hard to find.

With the A/C compressor out...        read full caption With the A/C compressor out of the way, we dropped the motor into place and installed the G-Force Performance crossmember, which bolted right up. It was made for the Malibu chassis with a 4L60E, and installing it was only a matter of tightening four bolts onto the framerail. Our factory TH350 linkage mated right up, allowing us to retain the column shifter. We also used Energy Suspension’s multi-application GM trans-mount (arrow) since the stock Firebird piece was too thick.

To install the S&P LT1 wiring...        read full caption To install the S&P LT1 wiring harness, we simply cut a 11/2-inch opening in the firewall, slipped the wires through, connected the color-coded harness into the similarly color-coded computer ports, and plugged each wire into its appropriate place. That’s it.

With the heater core taking...        read full caption With the heater core taking up the majority of the glovebox space, we ended up placing the computer on the floorboard, though we’ll eventually build a special mount inside the engine bay. The other extraneous wires are the leads that will feed signals to the Auto Meter tachometer, oil pressure, volt, and fuel gauges.

S&P’s neat pigtail harness...        read full caption S&P’s neat pigtail harness allowed us to jump the new alternator plug directly onto our old alternator’s wiring loom. Also, rather than stretching the old harness to mate, we used a 6-inch piece of 10-gauge wire and extended the main feed for that extra-sano look.

The S&P brackets and accessories...        read full caption The S&P brackets and accessories are way flashier than what we’re used to, but they solved the belt problem that we ran into after removing the original A/C compressor. The installation was a snap since the brackets only fit together one way. The power-steering pump now rests on the driver side, while the A/C compressor sits well above the framerail. If you prefer to use factory Corvette brackets, S&P occasionally has them in stock, or you can try a Corvette salvage specialist; unfortunately, they’re no longer available new from GM.

When installing the S&P brackets...        read full caption When installing the S&P brackets onto a Camaro or Firebird LT1, you’ll have to pull the integrated balancer/ pulley off the crank by removing the three outer bolts and using a pulley remover. Once apart, you’ll need to insert this aluminum spacer (arrow) to correctly align the serpentine assembly. If you’re using an LT1 out of an Impala, then you’ll have to either replace the balancer/pulley with a Camaro or Firebird unit and use the same spacer, or forgo the spacer entirely by using a Corvette balancer. Once completed, we fitted an off-the-shelf Gates 60.9-inch serpentine belt (PN K060900) to drive the system.

The S&P power-steering pump...        read full caption The S&P power-steering pump and reservoir features an AN-6 pressure line and AN-8 return line to fit newer-style steering boxes with O-ring fittings or older boxes such as ours with a flare fitting. The ability to clock the pump with this setup came in quite handy. The return-line fitting was a tad too close to our box, but the removal of two bolts allowed us to rotate the pump counter-clockwise by 30-degrees, which resolved the problem. For the lines, you can either have them built at a local shop or do as we did by mocking up the fit and faxing back the supplied hose kit diagram dimensions to S&P.

For the cooling system, we...        read full caption For the cooling system, we called Year One Next Generation and ordered a Be Cool ’95 Camaro LT1 replacement radiator. The 30x19-inch aluminum unit fit snugly, only requiring a slight modification to the Malibu’s lower radiator support. A metal tab interfered with the Be Cool drain plug, but a quick tap with a 5-pound hammer corrected the problem. To hold the radiator in place, we built custom radiator straps from 1/8x1-inch aluminum strips. As for the hoses, we capped off the heater hoses temporarily and used a set of inlet and outlet hoses for a ’95 Camaro. The passenger side was fine, while the driver side required cutting 4 inches off the portion that mounts onto the thermostat housing.

To install the S&P fuel rail...        read full caption To install the S&P fuel rail adapters, we pulled the retaining clip off the regulator on the return side of the fuel rail and used a Torx socket to remove the support bracket. Since the bracket is in an awkward position, we placed the socket onto a 1/4-inch wrench and taped it to avoid dropping it. Once we cut the feed line with a tube cutter, we were able to affix the new rail adapter and the supplied AN-6 lines.

The universal fuel-sending...        read full caption The universal fuel-sending unit (left) from Auto Meter came complete with everything we needed to fit it into our newly modified Rock Valley fuel tank. The top of our tank is recessed, so based on the new height we shortened the stem of the sender to 3 inches and cut the floater arm to measure 2 inches.

Every tank will be different,...        read full caption Every tank will be different, so don’t be surprised if you have to slot the top of the fuel sender plate. To connect the Goodridge feed and return braided lines to the intake pump, we used two 90-degree 3/8-inch NPT-to-AN-6 fittings. For the wiring, we wanted to be extra cautious and again used 10-gauge wire for the pump ground (A), power feed (B), and ran 12-gauge for the signal wire that leads into the fuel gauge (C).

Just seconds away from the...        read full caption Just seconds away from the big moment, we completed the final portion of the fuel system by connecting both the feed and return lines to the S&P rail adapters by using two AN-6 male union fittings (arrow). Once finished, we primed the pump several times to check for leaks, and attempted to fire up the LT1 for the first time. With three cranks, the LT1 was alive and kicking!

It’s now been a year since we first introduced our project ’78 Malibu (The Ultimate Malibu .) If you’ve been following along, you’ll also know that for the first time, rather than mindlessly dropping in a mega-horsepower big-block and topping it off with a nitrous unit, we decided to build our version of the ultimate daily driver. This meant it had to be reliable, retain civil street manners, and, being the performance aficionados that we are, it had to have the ability to power through the quarter-mile as well as being able to take a corner.

We started our Ultimate Malibu by first addressing its poor braking and handling qualities. We upgraded the meek factory 10.5-inch brakes to the massive 1LE 12-inch brakes and concurrently rebuilt the front end (Big-Brake Upgrade For GM A/G-Bodies.) Next, we installed the complete line of Hotchkis G-body suspension components along with Edelbrock’s IAS mono-tube shocks (G-Rated.) Of course there was also the brutal slalom and skid pad testing. This resulted in a stellar 0.83 lateral g-force on the skidpad and an awe-inspiring 6.63 seconds at 61.70 mph through the 600-foot slalom course. What we didn’t tell you was that the tired carbureted 305 seemed to know it was time to retire as it limped back to our shop. With its final gulp of air, the junk box made us push her through the shop’s bay door.

It was obvious from our last outing that we had the suspension dialed in, but now we had electronic fuel injection (EFI) in mind to help it pass California’s stringent emissions requirements. We just weren’t sure how we were going to combine that with performance and reliability. With the 305 on a permanent vacation, we spoke with Mark Campbell, the fuel injection conversion specialist and owner of Street & Performance (S&P) in Mena, Arkansas, who had an immediate answer to our dilemma. Campbell recommended using GM’s venerable LT1 with his custom wiring harness, and he put us in contact with Contemporary Corvette in Bristol, Pennsylvania. For under $3,000, we became the proud owners of a ’95 LT1 that featured a potent 10.5:1 compression, aluminum heads, and a stout rating of 275 hp and 325 lb-ft. It was delivered right to our door with all of its accessories (see “Getting a Signal” sidebar), the factory computer, and the original 4L60E transmission on a pallet. If you’ve ever made the effort to find a complete LT1 (the company has LS1s too) with a transmission and a guarantee that it’ll run, then you know just how much of a bargain that was.

With the motor in hand, the next question was assessing the level of complexity involved in transplanting a late-model motor into our pre-EFI sedan. Like you, we don’t have super mechanics that do all the wrenching for us, so it’s no surprise that we had an overwhelming amount of questions that needed to be answered. Would the LT1 really drop in hassle-free? What about a fuel system? What about a cooling system? How would we fit the 4L60E onto the crossmember? This is where Campbell once again proved to be an invaluable mentor. Having stuffed nearly every combination of fuel-injected engine into every conceivable package from street rods to musclecars—even trucks—his vast knowledge enabled us to get our project to where it is today. So follow along and see what it takes to stuff a factory-injected GM motor into your Malibu Classic and fire it up on the first try!

LT1 Install: Although we purchased our ’78 Malibu in California, it was originally destined for Arizona and tagged as a 49-state Federal car. Because of this, we weren’t burdened with smog equipment and miles of hoses languishing on the motor, which also made the removal as easy as it would have been on any musclecar-era vehicle. If you’re planning on doing this conversion with a car that originally housed a V-6, be sure to scavenge a set of V-8 mounts and swap them out. With the engine bay degreased and freshly fogged with both Eastwood’s Chassis and Underhood Black paint, we had high hopes of having the motor and tranny resting comfortably right away. Unfortunately, we found that the newer LT1 engine mounts are offset about 1½ inches on the passenger side in order to accommodate the A/C compressor bracket. A quick call to Campbell told us that our options were to either notch the frame or use one of S&P’s serpentine bracket and pulley kits to relocate the compressor. Considering that our welding skills are a far cry from sensational, we went with the bracket kit. With the brackets on order, we removed the A/C compressor and mounted the old 305 engine mounts where the compressor once sat. With some maneuvering of the engine hoist, the engine-trans combo dropped in beautifully. Mounting the tranny was easy thanks to G-Force Performance’s nifty engine-swap crossmember.

The new durable steel crossmember is designed specifically for G-body owners looking to install a 4L60E or TH700-R4 (G-Force also offers crossmembers for TH200-4R applications), and it features a dual hump to accommodate a true-dual exhaust system. At only $189, the price is very reasonable compared to the cost and hassle of fabricating a new crossmember. With the new drivetrain positioned, we found that the motor sat relatively low and offered plenty of engine-to-hood clearance. The stock Camaro exhaust manifolds exited free of obstruction, and there was ample clearance between the 4L60E and the trans tunnel. With the exception of the motor mount causing a few hours worth of frustration, it’s as if the LT1 was designed with the Malibu chassis in mind.

Fuel Plumbing: Unlike EFI systems, a carbureted engine’s fuel pressure demands are low, averaging only about 6 psi. On the other end of the spectrum, an EFI setup requires 40-plus psi, which obviously means some fuel system changes are in order. First we replaced the low-pressure rubber hoses with high-pressure braided stainless lines. We also needed a fuel tank with internal baffles to prevent the pump from sucking in air should the fuel level ever get low. We could have sumped the stock tank but opted to go with more of a factory-style system, mainly because if we ever have pump failure in the middle of nowhere, chances are that a replacement-style in-tank pump will be much easier to acquire than a trick external unit. To do this, we sent a brand-new stock replacement tank from SPI Distribution in Medford, Massachusetts, to Rock Valley Antique Auto Parts in Stillman Valley, Illinois, to modify it for our needs. Rock Valley first recessed the top of the tank by a ½-inch to prevent the fittings and fuel lines from hitting the bottom of the trunk floorpan. Rock Valley then installed a high-volume in-tank pump rated at 42 gph at 48 psi and cut an additional hole adjacent to the pump for a fuel-level sender.

For the fuel lines, we contemplated using prebent hard lines, but we later decided that AN-6 (3/8-inch equivalent) stainless braided lines from Goodridge would be much easier to route. Starting out back with the tank, we used two 90-degree 3/8 NPT-to-AN-6 fittings for both the feed and return. We ran the lines over the rear axle and then routed them to the front of the car along the passenger-side framerail. Once they were up in the engine compartment, we used a pair of AN-6 male-to-male unions and connected the lines onto S&P’s trick rear-exit fuel-line kit. If you plan on running the braided line, do yourself a favor and order this kit. S&P’s rail adapter is exceptional, and the kit includes everything necessary to attach the factory fuel rail onto AN fittings, making the job a breeze. All said and done, the fuel system was definitely the easiest portion of the installation—it took less than four hours to wire the pump, assemble the fuel-level sending unit, mount the tank, and do the final plumbing.

Wiring: The Fun Stuff: Wiring can be a horrifying experience. If you have to wire up every last sensor and sending unit onto a fuel-injected motor that you’re not familiar with, it can quickly become a lost cause. However, the S&P harness that we used made the job a snap since each wire was individually labeled. It used the same type of Weatherpack-connector as the factory system and plugged in effortlessly. Even the fuel pump relay is pre-wired and integrated into the harness. All it took to make the EFI pump functional was to connect the wire labeled “Hot lead to fuel pump” to the positive side of the in-tank pump. So if the only thing preventing you from dropping in an LT1 is the fear of wrestling with the OE harness, then get the S&P harness. It really does make it as easy as we claim.

Final Two Cents: Updating your car to the new millennium with fuel injection can be a challenging task for those unfamiliar with the technology. However, should you decide to take the plunge and follow in our footsteps, then know that it can be accomplished with a reasonable amount of time and money. The fact that we’re using a factory computer programmed by GM offers many benefits. First we don’t have to fiddle with any laptops or deal with tuning issues. Second, we can later hop it up with any late-model performance parts designed for its F-body donor. Although we still have some issues to address—including a driveshaft, an electric fan assembly, and an exhaust system—you can bet that the next time you see our Ultimate Malibu there will be a complete road test and evaluation. So, if you’re wondering whether a fuel injected LT1 was the best way to satiate our hunger for late-model performance, yes, it most certainly was!