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Troy LaCrone’s Approach to 7.90’s with a Street-Driven Camaro

Jeff Smith Aug 3, 2017
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The question was simple and direct, "Will you keep going after the eights?"

Troy LaCrone's answer was succinct: "I hope not!"

It appears that he knew his quest wasn't complete.

That was how our story on started in our January 2006 issue. At that time, LaCrone was experimenting with a nitrous small-block 1971 Camaro fitted with leaf springs and slapper traction bars that he eventually cajoled into running 9.19 at 140-plus mph. It was impressive because it looked more like a 12-second cruiser than a 9-second abuser. But LaCrone sold the Camaro and was tempted by the siren song of a couple of late model turbocharged Mustangs. Those attempts were less than rewarding for various and expensive reasons.

One day he decided to return to what he knew best, latching on to a 1968 Camaro ex-race car sporting a GM crate 572. At first, its performance was under-whelming. "It just didn't run right," LaCrone said. Though the 572 was built to make 620 hp, the car was barely capable of mid 11's. After some educated tuning, the numbers plummeted to 10.50's at 128 mph, befitting its big-block status. Yet LaCrone knew there was untapped potential.

The car also wasn't very pretty and LaCrone's cars all must look smart as well as run well. "It had a really crappy red paint job," LaCrone said. "It was chipped and dinged like a typical race car." So his buddy Tom Monehan of Monehan's Autobody massaged its abused flanks and replaced the tacky aluminum door panels with factory '68 Camaro replicas.

At this point, it was still just a back-halved, coil-over, ladder-bar car, but that was tantamount to pure race car stuff for a guy familiar with slapper traction bars and leaf springs.

The big push came with what LaCrone calls Phase 3 - a Steve Johnson Induction Solutions nitrous plate commanded by a simple Edelbrock controller. With "lots of tuning" LaCrone transformed his pedestrian 10-second street car into an 8.90 sprinter at 150 mph on what LaCrone admits was a "perfect pass in great weather."

Now for most of us, this would have been sufficient, but good enough just isn't in LaCrone's vocabulary. Call it an eccentricity. Whatever your preference, any new achievement merely pushes the goal farther out, not unlike the carrot dangling in front of the patient mule who just keeps pulling.

Up to this point, the 572 was not unlike the way it came from Chevrolet Performance in the 620 hp configuration. That meant a 254/264 degrees at 0.050 hydraulic roller camshaft with 0.632/0.632-inch valve lift, a set of Chevrolet aluminum rectangle port heads, and a single plane intake. LaCrone changed all that by taking it to Chris Straub of Straub Technologies in Piney Flats, Tennessee.

Working with Straub, he bumped the compression from 9.6:1 to 10:1 adding a set of Diamond nitrous pistons for durability and to push the top ring a touch farther away from the top of the piston. Total Seal rings added sealing while upgrading to ARP 2000 rod bolts for a little rpm insurance. The biggest move was to a set of AFR 335cc intake rectangle port heads with 2.35-inch valves a small amount of pocket porting. This pushed the intake flow well over 400 cfm, creating an abundance of flow that is always welcome.

You would expect that Straub would certainly tag a mechanical roller for this combo, but LaCrone didn't plan on spinning the engine much beyond 6,500 rpm, so breaking with tradition, Straub went with his own spec 272/274 at 0.050 hydraulic roller with 0.731/0.714-inch lift and Morel lifters that are more than capable of high rpm abuse. Straub even reused the GM 1.7:1 aluminum roller rockers but added an AFR stud girdle for added support.

Externally, Straub also ported an Edelbrock Super Victor Dominator intake that he matched with an AED 1,050 cfm 4500 series carburetor and dumped the HEI in favor of an MSD 6 ignition. On the engine dyno the N.A. version cranked out an impressive 816 hp. Then they hit it with a "conservative" 350 shot using a new Induction Solutions plate and solenoid package and that pushed the power into the four-digit zone with a 1,202 hp peak at a mere 6,400 rpm. All was ready for a new assault on the track.

Up to this point, the car was still running on a set of 31x14x15-inch Hoosier slicks on the track, but even the greenest of rookies knows you can't hammer tires with a full 1,200 hp and not turn them to smoke. As with all four-digit power combinations, a certain amount of finesse is required. LaCrone decided to try Edelbrock's progressive nitrous controller both because it was priced decently and it didn't appear to be overly complex. Despite its apparent simplicity, the six-wire box offers significant control to gradually introduce power by pulse-width modulating the nitrous and fuel solenoids to progressively add more nitrous and power.

We caught up with LaCrone in 2016 to recount his impressive gains, and at that point the car had already run high 8.60's but it seems like every weekend the car went quicker, with tenths falling like the ticks on the e.t. clock. Eventually, the car settled in with its personal best at the end of the season with an 8.24 at 167 mph. If you sensed a pattern forming here so did we. It was obvious LaCrone wasn't going to be satisfied until the Camaro ran in the 7's. He climbs mountains because they are there.

Most 7-second cars lean more heavily toward the race car side of life than the street car side of life. But LaCrone was determined to retain its street manners. He knew his Camaro was overweight yet he insisted on retaining all stock sheetmetal and glass except for the hood. That meant the car would need chassis work. That's when the Camaro visited Marc Beilman at Beilman Fabrication where he upgraded the roll cage to 7.50 cert while adding a completely new round-tubing front clip. The rear suspension was retained.

"I have a theme work with the best people you can and you will get the best results," LaCrone said. Even with a decent suspension, 7 seconds demands big horsepower. So LaCrone went back to his buddy Straub where they collaborated on an even more powerful 572.

Working with Straub's Scott Foxwell, LaCrone said "I told them it's a street car but I wanted to run 7's" and they started by bumping the compression to 11.0:1 with new Diamond pistons and Oliver Billet Max connecting rods. Total Seal again got the call for a set of AP steel rings to take the abuse of elevated nitrous consumption. The Straub/Foxwell team came up with a much more aggressive solid roller cam this time with 276/286 degrees of duration at 0.050-inch tappet lift pushing the lift to 0.773/0.748-inch. The big cam meant peak power would occur at higher rpm, so LaCrone dropped in a set of Morel Black Mamba lifters. While they retained the AFR 335 heads from the previous package, additional porting pulled yet a little more flow out the heads with a combination of 2.35-inch stainless intakes and 1.88-inch Inconel exhaust valves. Straub spec'd the valve springs and the Smith Brothers 7/16-inch pushrods that completed the valvetrain. They also performed additional porting on the intake and added a larger 1,200cfm AED carburetor - until the first dyno test.

LaCrone's friend Chris Calkins assembled the engine and then LaCrone delivered it to Chris Nowak of Nowak Racing for a serious dyno tuning. "He loves to find hidden power," LaCrone says and there was plenty to uncover. The first carburetor they tried seemed down on power and eventually they lasered in on a larger 1,250 cfm AED Dominator that the engine really seemed to like.

This is when Nowak's knowledge and an interesting TFX pressure transducer package helped guide them. The system uses eight pressure sensors to record and plot the in-cylinder traces throughout all four strokes. Nowak says that he has only recently purchased the system and is still learning how to take maximum advantage out of the data he retrieves.

Nowak began the tuning process with a very straightforward approach. "The reason for using the in-cylinder system on Troy's engine was two-fold. 1. To get all we could out of it naturally aspirated and prepare the engine for nitrous 2. To make sure it would safely make enough power to achieve a 7-second 1/4mile e.t. So, naturally aspirated, we used O2's to get close but along the way we were collecting combustion location data to back up our tuning choices as well as put the finishing touches on timing per cylinder."

The details are intriguing, but the headlines are Nowak stagger-jetted the carburetor to idealize the air-fuel mixture for all eight cylinders which added roughly 40 hp to the total. Then retarding individual cylinder timing was worth an additional 10 hp. Amazingly, they pulled timing in five of the eight cylinders, retarding one hole by an astonishing 8 degrees and 7 on another with no loss of power. This produced the cleanest normally-aspirated runs by reducing negative work, which also made the nitrous runs that much safer.

Starting at roughly 850 hp, Nowak's tuning efforts resulted in a normally aspirated peak of 908 hp at 6,900 rpm. This demanded roughly 45 separate pulls on the dyno to achieve, but then only 5 nitrous runs, gradually increasing nitrous from 150 to 500 hp eventually generating a peak nitrous effort of 1,427 hp using only 12 degrees of total timing. All the effort put into the normally aspirated tuning made the nitrous runs exceptionally clean. That led to confidence that the engine could make multiple passes at the 500 hp nitrous level while minimizing damage to the engine. Of course, that means LaCrone already has plans for a 650 hp effort.

There's tons more to this story. LaCrone's current fixation is running Drag Week in the normally aspirated big-block class with a goal of 8.90's without the squeeze using a new Circle D converter and to log 1,000 miles in between drag passes. We don't doubt he'll make it. Post Drag Week, Troy says he plans to go faster, "We are going to get after the nitrous system and upgrade to the new Induction Solutions controller and run some mid 7's."

1968 Chevrolet Camaro Three Quarter 2/23

If perception is reality, Troy LaCrone's Camaro might look like a mid-10-second street car, especially if you thought the funny car style cage was a ruse. Don't be fooled. This thing's a rocket.

1968 Chevrolet Camaro Engine Overview 3/23

Even opening the hood tells you very little. That's a 572ci Rat with a single four-barrel Dominator and a "single stage" Induction Solutions plate. What you can't see is all the elegant tuning that went into pushing this engine safely beyond 1,400 hp on nitrous.

1968 Chevrolet Camaro Interior 4/23

The interior view is a bit cramped with the requisite funny car style cage that is required when running as quick as this Camaro. Otherwise, the interior appears surprisingly stock.

1968 Chevrolet Camaro Drag Launch 5/23

On only his second run in the car with the latest combination, LaCrone ran a stellar 7.90 at 169 mph. He's now perfecting the Camaro's potential 8-second normally aspirated abilities with a converter and a deeper gear.

1968 Chevrolet Camaro Edelbrock Module 6/23

The Edelbrock nitrous controller is deceptively simple yet is allows LaCrone to dial in a relatively sophisticated pulse-width modulated solenoid control regimen.

1968 Chevrolet Camaro Carb 7/23

AED supplied the 1,200 cfm 4150 carburetor and just peeking out from under the carb is the single plate Induction Solutions Sledgehammer nitrous plate and solenoids that is a four-bar system. LaCrone says his experience with owner Steve Johnson has been exceptional.

1968 Chevrolet Camaro Race Results 8/23

For the non-believers, here's LaCrone's 7-second time slip. Note the 1.15-second 60-foot time, which is impressive for a 3,260-pound street car. LaCrone attributes much of that success to the 31.25x12.2W Mickey Thompson slicks. Slightly wider Hoosier Quick Times are used on the street.

1968 Chevrolet Camaro Engine On Dyno 9/23

This is Chris Nowak's dyno room. What is most surprising is that he built this whole system for his own satisfaction and use. Nowak is all about "learning and doing things right." "He fears nothing and goes after challenges with a smile."

1968 Chevrolet Camaro Passenger Door Panel 10/23

This carbon fiber plate mounts the MSD 7531 spark box that combined with a crank trigger allows individual cylinder timing, which allowed LaCrone's dyno tuner Chris Nowak to dial in the final tune.

1968 Chevrolet Camaro Fuel Gas Tank 11/23

The trunk features the ubiquitous fuel cell and battery leaving precious little extra room for the road trip that is Drag Week. LaCrone already has a trailer built and outfitted for the adventure.

1968 Chevrolet Camaro Valve Guage 12/23

Nitrous Solutions' Steve Johnson says the best way to preserve the sealing seat on the nitrous solenoid is to use an in-line gate valve to separate the solenoid from bottle pressure except during a run. The pressure gauge is an essential tuning tool.

Tech Notes

Who: Troy LaCrone
What: '68 Camaro
Where: St Claire, MO
Engine: This Rat started life as a 572ci GM crate motor with an iron Bow Tie block; it now has Callies crank, Oliver billet Max rods, Diamond 11.0:1 nitrous pistons, Total Seal AP Steel rings, and a Straub Technologies 276/286 roller with 0.773/0.748-inch lift with Morel Black Mamba lifters. The heads are ported AFR 335cc castings performed by Scott Foxwell with 2.35/1.88-inch stainless valves and Straub springs. The intake is a Foxwell-ported Edelbrock Super Victor mounting a 1,200 cfm AED 4500 style carb. Induction Solutions supplied the Sledgehammer nitrous system while fuel is fed by a MagnaFlow 500 pump. Ignition energy is created with an MSD 7 box (PN 7531) while the nitrous transitions via an Edelbrock controller.
Transmission: Hutch built the TH400 with a Circle D 5,600 rpm stall nitrous converter bolted to an SFI flexplate and feeding a PEM custom chrome moly steel driveshaft. There is a different Circle D converter now in the car to run Drag Week.
Exhaust: It's pretty simple with Lemons custom, 2 1/4-inch headers that step to 2 3/8-inch feed a 4-inch exhaust with DynoMax mufflers. It's a little loud inside the car.
Suspension: This year, LaCrone stepped up to a Smith Racecraft front subframe expertly installed by Beilman Fabrication that peeled a solid 150 pounds off the car while also making it safer. The rear is still a braced Strange 9-inch with 35-spline axles and still running basic ladder bars. Santhuff supplied the front coil-overs while Afco Big Guns control the rear. .
Brakes: When you run 170 mph, it better be able to stop. Wilwood four-piston calipers are fitted front and rear on 12-inch rotors.
Best Performance: 7.90 at 169.34 mph on nitrous with a goal of 8.90's normally aspirated.
Credit: LaCrone says this was entirely a team effort with immense help from all the above mentioned folks plus Brian Raymond, Scot Lowery, John Callies, Chris Sehorn, Mick Boyer, Jimbo at JCR Wiring and, of course, his lovely wife Tonya.

Photography by Greg Connoyer

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