From 1982 to 1992, the third generation of F-body reigned supreme. With its long nose, sweeping fastback tail, and of course those ubiquitous T-tops, it made the 1980s a great time to grow up as a gearhead. The problem is that if you want to live the fantasy of driving a sweet IROC Z28, you have to do so with whatever is left of the 150 horsepower the anemic Chevy 305 had to offer. Coupled with the 3,400-pound curb weight, there just isn't much to get excited about. This is why we yanked it out of our 1987 IROC Z28 and dropped in a direct-injected Gen V 5.3-liter L83, which more than doubles the previous power rating at 355 hp and 382 ft-lbs of tire-shredding torque. After all, muscle cars need real muscle.
We sourced the take-out engine from our local salvage yard. The engine is a 2015 L83 from a Chevy Silverado 1500. For $1,700, we snagged the complete engine, ECM, and fuel pump controller. Most salvage yards charge extra for the accessories, which include the throttle body, starter, alternator, AC compressor, and sometimes the coils. For an extra $50, a starter and throttle body came along for the ride. The other bits are coming from Holley. Unfortunately, our local yard does not sell wire harnesses; they just cut them off at the plug. We will be using an aftermarket retrofit harness from Howell EFI.
In order to fit the LT engine into the Camaro, we need a few parts. The third-gen is not the easiest to swap; many choose to swap the entire K-member when doing an LS swap, but we don't have to go that route. It can be done easily enough with some parts from Holley and Trans-Dapt. We will also be wiring the engine with sending units for AutoMeter gauges. The biggest issue for most swaps is the accessory drive, and the LT is no different. The factory accessory drive will not work with AC in the third-gen, period. The AC compressor is mounted low and tight to the block, which hits the K-member and subframe, making this a non-starter. Holley's standard LS/LT high-mount accessory drive is a perfect fit. The only thing you have to move is the overflow tank on the passenger side. The Holley drive removes the offset LT water pump and swaps in an LS-style water pump. It also uses the truck crank pulley, which is nice because we already have one.
There are three different versions of oil pans for the LT-series engines, and not one of them is suitable for most passenger car swaps. We picked up a Holley 302-20 LT swap oil pan that fits significantly better than any of the stock pans. Mounting the engine into the chassis requires adapter plates, and Trans-Dapt got the job done. They offer three versions:1 1/8-inch back, 5/8-inch back, and 5/8-inch forward. This references the engine setback from the stock LT location. The 1 1/8-inch back adapters place the bellhousing plane in the stock position (the same as an SBC), 13 inches from the clamshell to the bellhousing pad. This works well for most swaps, but for third-gen F-bodies, this only works in non-AC cars (or aftermarket AC). The AC box on the firewall is fairly large, and simply does not clear the passenger-side valve cover. We swapped in the 5/8-inch back adapters, which positions the engine a half inch forward of the stock bellhousing plane. This will require some adaptation in the transmission crossmember (which has to be done regardless), but the engine clears the AC box with just a minor trim of the bolt flange on the box itself. There is still plenty of room for the radiator, and this gives the engine a little more breathing room to the firewall, which is good, as the heater hoses are super close too.
To round out the swap, we are installing an American Powertrain T56 Magnum 6-speed with their clutch kit and release bearing goodies, a new fuel system, swap harness from Howell EFI, and a new exhaust system, which we will cover in upcoming articles.
Let the horsepower injection begin!
The process starts with removing the entire accessory drive, including the water pump. The crank pulley can remain in place.
In order to clear the new LS-style water pump, the VVT solenoid must be re-clocked. The Holley kit comes with a billet aluminum clocking ring and a new harness.
There are no extra water ports, so you have to drill and tap the top of the new water pump to get a secondary temp sensor for aftermarket gauges. You could also drill and tap the passenger-side water pump adapter.
You need two sets of gaskets to assemble the water pump. We used the steel gasket to the seal block, which has a built-in bolt retainer.
With the pump bolted on, the intermediate LT brackets go on. This is what adapts the Holley LS accessory drive kit to the LT heads. Note the factory water temp sensor has been installed into the pump spacer and the wiring is routed through the cutout in the adapter. This is not accessible once the main bracket is in place, so don’t forget.
A new type-II power steering pump comes with the kit. This system requires a remote reservoir.
There are two options for the lower idler pulley, this allows for a shorter belt to be used if necessary, such as the non-AC version.
The completed Holley high-mount accessory drive looks clean and keeps all the components out of the way. We used the Sanden SD7 AC compressor that came with the kit.
We pulled the oil pan, saved the bolts for reuse, and then scraped the block. There is no gasket; the pans are glued to the block with silicone.
After cleaning the oil port with a bottle brush, the pickup tube was installed with the supplied gasket and bolts.
Next, we installed the Holley windage tray. Don’t forget to use medium thread-locker on all of the internal bolts. This pan is also available in a drag race version with a trap door sump.
Each orifice seals to the block with an o-ring; there are three. Do not leave them out, and check the block before installing the pan, as the old ones tend to stick to the block.
Unless you are using an oil cooler, you need to install the bypass cover. The pan comes with this nice billet piece. You can drill and tap this for an oil port. (Holley sells one that already tapped as well.)
The front and rear covers on the LT block require a wider patch of silicone, as these are leak-prone areas. Make sure you run your bead behind the bolts (to the inside of the block) so oil does not leak through the threads.
There is a very specific torque sequence for the oil pan bolts; it is not as simple as center-out. Make sure you follow it.
The truck LT engines use a vacuum pump, which bolts to this boss on the driver front side of the block. This does not fit the chassis, and must be removed. There are two ports: the upper is pressurized oil, and the lower is the return. They are both M12 x 1.75 thread. You can use the upper for a sending unit if your motor mounts clear. Third-gen Camaros use clamshell mounts, so they don’t clear. Use medium threadlocker on the plugs.
The Trans-Dapt adapter plates make the swap easy, but the third-gen Camaro requires moving the engine forward a half inch. The upper adapter is the one we used; the lower plate puts the bellhousing in the stock position, which is too close to clear the AC box and heater fittings
We kept the factory-style frame pads, which are the clamshell style. This means the upper shell is quite large and obscures the oil port. We had to trim the lower corner. This won’t affect the strength of the clamshell.
While it may seem counter-intuitive, you have to drop the engine into the chassis with the front of the motor angled down. This allows the mounts to drop on the pads and then you can lower the rear. Otherwise, your hoist chains hit the top of the cowl, pushing the engine forward. The intake and exhaust manifolds must be removed, as well as the wiper motor and overflow tank.
Here is the interference with the AC box. We trimmed off the bolt and about an inch of the plastic in front and behind it. Now there is plenty of clearance.