LT1 F-bodies have good looks, great performance, and huge potential. And lately, they're getting damn cheap, too. Look on some of the big trader Web sites and you can find a running example for under three-grand! So if you're in the market for a high-mileage Z or 'Bird, or have one already sitting at home, lucky you.
Of course, most of the low-ducat rides out there have between 80,000 and 170,000 miles on them. That means some of the car's original components will, by this time, be in sorry shape. Along with those low prices comes a catch: the LT1 engine was the bridge between the archaic GM small-block and the futuristic Gen III/IV. This torquey work-in-progress produced good power, but was more complex than it had to be, and suffered because of it. Oftentimes, newbies find themselves way over their heads when something goes wrong.
GMHTP wanted to update and enhance an LT1, and 83-year-old speed demon King Rhiley offered up a 119,000-mile Z28 that was so near factory it was sick. It's go-time.
We approached Chatsworth, California-based Los Angeles Performance Division to do the work. This crew, which works out of an enormous Canoga Avenue shop with several lifts and a Dynojet, specializes in Gen III Corvette performance. However, they were still willing to tear into the LT1 motor in the name of science.
The plan was to baseline the car on LAPD's dyno, replace the worn-out OEM stuff, then bolt up some high-quality speed parts. Wearing only an airfoil and air intake, 236 horses and 280 lb-ft of torque showed at the rear wheels. The baseline dyno was without incident, but due to the LT1's age and complexity, we hit a few bumps later on. Read on to see what happened--and learn how to make aging LT1 upgrades hassle-free.
Tips And Tricks
In 11 years, this F-body has been treated to high-speed highway runs, big-city traffic, temperature extremes, and nothing but the best fluids and components.But after 119K, we felt it was high-time to replace some of the LT1's integral parts. The original timing chain was stretched out, so a high-quality Comp single roller was installed to avoid problems in the future. The original valvesprings had gotten lazy; Comp's 983 springs, 751 retainers, and 613 locks added top-end rpm. Comp also provided stock-length hardened pushrods and 1.6-ratio roller tip rocker arms. The rockers increased stock-cam lift from 0.448/0.459-inch with the 1.5 OEM rockers to 0.478/0.489-inch, and increased power in the process.
Ignition is always a touchy subject when LT1s are concerned. But in the aftermarket, what was once a drought is now a flood, with several large and small companies marketing refined Optis or coil conversions. With reliability in mind for this mildly modded and stock rev-range Camaro, the billet aluminum Dynaspark was our choice. This LT1 distributor shames the OEM unit with its high-quality components and blueprinted assembly process. It's rebuildable too--great when GM Opti prices are out of sight. We immediately noticed a smoother idle.
To avoid ignition problems down the road we replaced the stock wires and coil with an MSD Blaster coil and some new black Super Conductor wires. The black wires make for a stealthy look in a stock engine bay.
Exhaust upgrades can be dicey. You want the extra power but pray that larger aftermarket tubes will somehow mirror the factory system's turns--because if it doesn't, it's rattle city. We'd been watching Kooks' foray into the LT1 for quite some time, so when its 1.75-inch LT1 long tubes became available, we jumped on them. LT1 F-bodies have plug access and ground clearance problems with long tubes, but the Kooks pipes offer good plug access and very good ground clearance. Throw in the high-quality stainless construction and huge power gains over stock manifolds, and the Kooks headers/Y-pipe combo is tough to beat.
Complementing these high-zoot headers is Borla's stainless, 3-inch single-cat exhaust system. The Borla sound is just as unique as the Cat-Back's adjustments, with block-off plates ranging from "near stock" to "arrest me" to suit its owner's taste. And to top off this quality system, the "26" intercooled tips are the coolest.
It takes a dead-on PCM calibration to turn this pile of parts into a cohesive unit. Pcmforless has built a solid reputation for delivering a great mail-order tune to its customers, so we contacted Bryan Herter with our list of upgrades. We filled out Pcm's extensive order sheet and requested a transmission shift slightly firmer than stock. A few days later, a recalibrated PCM was in our hands, so we sent ours back as a core, installed the LT4 knock module, and bolted it in. During wide-band dyno and street testing it's evident that Herter changed what was necessary and left everything else alone. The Camaro still idles and transitions like a stock car--albeit quicker with the new go-fast goodies. The slop is gone from the auto trans, but it's not harsh. Our Z28's knock retard and high air/fuel ratios come from the wasted stock fuel pump, not this tune. For only 99 bucks you get a dead-on tune and a free recalibration within 60 days--for anyone who's new to programming chips/PCMs, it's a smokin' deal.
LT1 Parts Used And Why