700 HP (OR THEREABOUTS)
The world needs another LS-powered early Camaro? it really doesn’t, but it seems no in the performance industry got the memo, cuz guys are building the ubiquitous combo in soaring numbers, and manufactures are releasing new swap parts like popcorn. Holley is chief among’em and has a complete line of LS-engine swap parts including engine mounts, trans cross members, oil pans, accessory drivers, headers, exhaust systems, intake manifolds, fuel components and EFI conversations. To prove how easily late model engines can be retrofitted into an old car with Holley parts, the company made a foolhardy gamble, sponsoring challenge for us guys from the Roadkill show: we’d have to install an LS engine and EFI from scratch for three days in front of a live-video-feed audience, and do it from the floor of the Performance Racing Industry trade show,. Immediately after the show, we’d have to drive the car 2,400 miles from Indy to California to escape December weather so we could drag race it. It’s as if no one at Holley had ever seen the level of fail that litters the plot if most episodes of Roadkill.
If you’re not familiar with the show, go to YouTube.com and search “Roadkill” and you can’t miss the 25 episodes we’ve posted so far on the Motor Trend channel. Look for “Roadkill Episode 24” and you’ll see a story about the fun parts of the adventure. You can also watch replays of every moment of the 24-plus hours of live video coverage of the engine swap by searching “Roadkill Live.”
But now, some off screen dirt, tech info, and opinions about the swap. If made for a whole lot of learning by a couple of luddites; myself and Mike Finnegan.
ENTER THE OLD-SCHOOL CRUSHER CAMARO
You probably know HOT ROD’s ’67 Camaro called the Crusher. It’s been around here for 20 years, ever since we rescued it from a government car-crushing scam. It’s had a number of engines; the original inline six, a smog-friendly 406ci small-block, a632ci aluminum big-block, an HT383 crate engine, and most recently a 489ci big-block with an 8-71 blower. Now it’s gonna be fed its first LS-series engine.
When we turned the Crusher into a late-‘70s/early-‘80s-looking street machine in 2009, many people lost their minds and said we’d totally ruined the car with a stupid look and antiquated, dysfunctional parts. When we announce the plans for the LS swap in late 2013 we also took flak – this time from people who screamed we were about to totally ruin the car with a stupid look and modern, boring parts. This was going to be a war of the worlds.
In its’70s world, the Crusher was living large with an engine big on character and power but with tame specs. It was a 489ci (4.280×4.250 inches) big-block with Seat’s cast crank and rods, SRP forged pistons with 8.95:1 compression, and now-discontinued Holley oval-port heads. The blower was a Weiand 8-71 blueprint and Teflon-striped by the Blower Shop, and the carbs were twin 750-cfm HP-series Holleys. We originally dyno tested it using a Crane Saturday Night Special flat-tappet cam with 236/246 degrees of duration at 0.050, 0.553/0.571 lift with 1.7:1 rockers, and an LDA of110. With the cam and a 25-percent-underdriven blower-drive ratio, the peak boost was a mere 4.8 psi and engine made 717 hp at 6,200 rpm and 674 lb-ft at 4,500. We later installed a hydraulic-roller cam from Comp Cams, an XR276HP with 224/230 degrees of duration at 0.050, 0.510/0.510-inch lift, and a 110-degree LDA; that’s micro-scopic for a blown Rat motor, but it worked amazingly well with the meager boost. With that small cam, a Superflow chassis dyno reported 520 hp and 500 lb-ft to the rubber. Hence the “thereabouts” disclaimer in the title; as installed in the car, the Rat probably made around 650 crank horsepower.
The rest of the big-block drivetrain included a Gearstar-built GM 4L85E, which to this day is the best automatic trans we’ve ever had in terms of beef and shift quality. The rearend was a 9-inch with 3.50:1 gears and a Moser Wavetrac limited-slip for 35 spline axels.
In that trim, the Crusher made round trips from L.A. to Phoenix and Salt Lake City. We took it to cruise nights and commuted tin it and were amazed how drivable it was, the tiny camshaft helped prevent blower surge and overbeating. The car would immolate the tires with just a quarter-throttle stab. From 50 mph it would down shift and get smoldery and sideways at WOT. The torque and the push into the seat were ungodly. Bad news; 6-9 mph. Worse news; we had The Blower Shop rebuild the super charge twice, once due to back firing from an ignition problem and second thanks to someone repeatedly backfiring it because they didn’t know how to start it.
At the drag strip, we were happy. After driving the car 40 miles to the track, we bolted up Hoosier 30×9.00 radial slicks, did minor tuning, and ran 10.62 at 126.32 mph on 91 octane pump gas. It could have been quicker with more gear, as it ran through the lights at a low 5,200 rpm with the 3.50:1 cogs; the power peak is closer to 5,800, so 3.90s would have been better. The car was also heavy: 3,499 pounds with its aluminum Center Lines, and certainly a little more with the race Crager S/S wheels. Add the driver and some video equipment, and it was down the track at 3,670 pounds or worse. We obviously could have swapped some blower pulleys and made more power and a quicker e.t., but that’s all bench racing at this point.
NEW-SCHOOL POWER
For the LS-swap challenge we needed something that would play ball with the big-block and wouldn’t look like every other Pro Touring LS1. We borrowed a 427ci (4.130×4.00 inches) LS7 from Mast Motorsports, the company that builds all sorts of custom LS engines and produced cylinder heads that have made the biggest power in every LS-head shootout we’ve done. Topping this 427 were Mast’s LS7-port, 305cc Black Label heads. The bottom ends used all forged components, Mahle pistons for 11.25:1 compression, and a conversion to wet-sump oiling (factory LS7s are dry sump). The cam is an off-the-shelf Comp Cams hydraulic roller with 252/267 degrees at 0.50 tappet lift, 0.624/0.624-inch lift, and 115-degree LDA (it’s grind number 54-474-11)
We made the guys at Mast top the engine with an intake they’d never used: a Holley Hi-Ram tunnel-ram base (PN 300-229 for the LS7) with a lid (PN 300-216) for twin 4150-style, 1,000-cfm, four-barrel throttle bodies (PN 112-577). That’s where the crazy looks came in. We never executed a comparison with other intakes, but the collective wisdom agreed the tunnel ram’s plenum was a little too much for the low-compression 427, and that compared with a typical LS composite intake or single four barrel, it probably gave up midrange torque while adding horsepower numbers at the top end. It was all controlled by Holley’s top EFI ECU, the Dominator V2. The Holley injectors were rated to 48lbs/hr at 43 psi of fuel pressure, but our system pressure was 58 psi for a potential of 55 lbs/hr.
The scream to redline sounded like this: 710hp at 6,900rpm and 577 lb-ft at 6,100 (though the torque was flat starting at 560 lf-ft at 5,000 rpm). That was in very cold conditions on a 91-octane fuel. Owner Horace Mast dialed down the timing a little for 690 hp and 570 lb-ft out the door, knowing we’d run junk California gas. By the time we added smaller headers (1¾ in the car instead of 2-inch on the dyno), a full exhaust system and air cleaners, it once again explains our 700 hp “or thereabouts” caveat.
THE ENGINE-AND-TRANS SWAP
The point of this exercise was to test the Holley swap parts, and this sums up that experience: we had our old big-block and 4L85E transmission out and the new LS7 and 4L70E bolted into the car in just eight hours (with many interruptions for video). The key is that Holley, under the Hooker brand, has scienced out combinations of engine mounts, transmission crossmember, headers, and exhaust systems that all work together to place the engine and trans in the right spot so that the exhaust parts fit perfectly. Its way better than mixing and matching stuff and pounding headers with hammer, we can’t say enough about how well it fit together. Granted we have manual steering that has better header clearances that a power steering box, but we could have thrown the headers at the car from across the room and they’d have landed in the right spot. See the photos for swap details.
All of the swap parts are contingent upon the use of a T56 six-speed manual or an automatic transmission from the late-model, two-piece housing, small-case family: 4L60, 4L65, 4L70, or 4L75. It’s as yet uncertain if the larger 4L80/4L85 series will work with the Hooker headers, and it certainly won’t work with the current Hooker crossmember. Therefore, we begrudgingly removed our 4L85 and called Gearstar owner Zack Farah to break the news. He said “the 4L60/4L70 isn’t the trans I’d use for 700hp, but if anyone can make it work we can.” In other words, do as we say, not as we do, and try not to have 700-plus horsepower with a 4L60 unless you want to spend the huge bucks making the transmission survive. That said, our fresh Gearstar 4L70 took a whole lot of drag strip and burnout about and it’s still ticking. But we’ll get to that later.
DOMINATOR EFI
The other element of the LS7 swap was that it required Crusher to give up its carburetors for EFI, and like the rest of the swap we had to install it as part of our three days on the floor of the PRI show. EFI came down to the last day. The only portion of the conversion that we’d prepped in advance was the fuel system, as Grant Peterson in our tech center got a reproduction fuel tank from Classic Industries, cut it open and added an internal fuel sump and baffles, then plumbed it for the Holley Dominator electric pump. For the engine swap, all it took was a swap from a carburetor-style fuel-pressure regulator to an EFI version, the fuel system was handled.
The wiring, however, needed to happen from scratch. We used Holley’s highest level ECU, the Dominator V2 (PN 554-114), to control the fuel injection, the electronic transmission, and three electric fans (two on the BeCool radiator, one on the trans cooler), and planned ahead for it to drive a dry nitrous system. The thick bundle of wires for all the sensors and controls was daunting, and the reason many hot rodders have feared EFI for years.
Once we tore into it, it proved less difficult than expected. We cleaned up a lot of electrical spaghetti by tearing much of the old wiring out of the car: gone where the ignition system, the gauges (ousted in favor of Holley’s PN 553-103 5.7 inch touch screen), the alternator exciter wire, the old stand-alone trans controller, and the switches for the fuel pump and fans. It was all replaced by various Holley harnesses: PN 558-405 for the trans control and PN 558-406 and PN 554-100 for the accessories. Those harnesses are pretty well labeled with what goes where. Only the optional accessory controls really required a hard look at the instructions.
The biggest challenge with the installation is simply routing the huge harness. You’d wince as we did while hogging at least a 1½-inch hole in the firewall to pass through the connectors. Also, the Dominator ECU is humongous; it can process a lot of functions, but still seems big, with a footprint of about 13×6 inches. On short notice, we couldn’t cleanly mount under the dash of our Camaro that still has a heater box, so we Velcro’d it to the top of the trans tunnel near the firewall.
ON THE ROAD
We did it; a complete engine-and-trans swap with exhaust and a conversion to EFI in just three days – about 20 hours of wrench time in total. We fired up the engine at 4:15 pm, just 15 minutes past the deadline. The next day’s snafu involved a blown trans-cooler line, 20-degree weather, Funny Car racer Tony Pedregon and Pro Stock racer Steve Schmidt. We thank both of those race shops for the help which you can see in the detail in episode 24 of Roadkill. A date late, we were back on the road.
The first few hundred miles with the LS7 involved trepidation over driving with new parts and 700 hp in the snow and ice. Our first failure was a dead electric fuel pump, which the guys had predicted because of three installation issues: 1) The Dominator pump (PN 12-1400) was mounted vertically instead of flat, which can tend to cause aeration, 2) the pickup of the pump was about an inch and a half above the bottom of the tank, and electric pumps always prefer to be fully below the level of the fuel in the tank, and 3) we had plumbed the return-style-fuel-pressure regulator before the fuel rails, a setup that taxes the pump more than rigging the regulator after the rails. The good news is that the Dominator pump uses two separate motors inside one billet-aluminum housing, so we were able to swap the power wire from one pump to the other to get going again. The real reason for the twin pump is to be able to progressively stage fuel delivery, sunning one pump at idle and cruise, and kicking in the second one at WOT or under boost for making huge power.
With day-one failure complete, we settled into cruise mode, with a passenger constantly learning the EFI computer program and perfecting the drivability of a base tune that was extremely flogged, cell by cell, when the engine was on the dyno at Mast Motorsports. Having to tune with a laptop computer is another reason why many hot rodders shun EFI, but we glommed into it and wondered how we ever lived without it, if you have a solid grasp of all of a carburetor’s fueling circuits and their functions, and knowledge of how ignition timing effects engine operation, you can easily understand the Dominator EFI just by playing with the all the various screens. For example, by messing with fuel enrichment for cold-start, after-start, and acceleration, and modifying them for different inlet air temps and coolant temps, we were able to get the engine to start and idle at the first turn of the key in 16-degree weather. Messing with timing and the fuel tables in light-load cruising conditions, we achieved 15-17 mpg at 75 mph on the highway.
The Moser 3.50:1 rear gears, the Yank lockup converter in the Gearstar 4L70 Trans, and the 0.696c1 overdrive, gave us about 2,200rpm at 7 mph. With the Dominator ECU controlling the transmission, a plug-in to the computer program allowed us to also tune shift points. Line pressure can also be controlled, though we didn’t mess with the baseline Holley had set for us for fear of our own lack of knowledge about the trans operation. We had no fear, though, about exploring every screen and marveling at all the functions the computer can control, and we loved tuning on the fly and getting immediate results with there in the seat rather than having to hop out and turn screws. The dominator is also an impressive data logger. We realize that most of these functions are age-old capabilities of aftermarket EFI units, but this is the first time we’ve played with advanced software that made us feel like we knew what we were doing.
By the time we’d gotten comfortable with the EFI, we were also old friends with the new engine and trans, and we were in Arkansas with no ice on the roads. We began to really drive the car. At low throttle positions, the naturally aspirated small-block was a letdown compared with the big blown big-block. It just seemed piggy; the brute torque wasn’t there. Even so, cruising at 50 mph and double-downshifting to Second while stabbing it to WOT was a life-altering experience. It didn’t over power the tires like the Rat motor, but as rpm began to shrick, the thing would warp those lunchtime tacos right around your spine. Finnegan announced it was faster than the big-block. It still wasn’t so sure.
What I did know was that the Crusher was a better driving car overall. The engine was less finicky, and it steered, handled, and stopped better without all the weight on the nose. Sans blower, we could finally navigate around a Honda in the right hand lane without a spotter.
AT THE TRACK
Back at our ship, we verified that gravity affords a huge advantage to the all-aluminum small block. Between the engine, the smaller 4L70 trans, and the QA1 coil covers we’d added to the front suspension (so we could adjust ride height after the engine swap), the Crusher had dropped 343 pounds. The total race weight without driver was now 3,145 pounds.
Because the new engine made power all the way to 7,000 rpm, we gave it the advantage of a gear swap since it would struggle with the 3.50s. Estimating the car would run 135-135 mph in the quarter with the LS7, we opted for 4.57 cogs to go with our 30-inch Hoosier slicks. The Crusher runs a 9-inch rear axle with 35-spline axels; 28-spline is stock for most passenger cars, and 31-spline is common to trucks ad aftermarket upgrades. The beefier 35ers limit the differential choices, and in the old days, only lockers and spools were available. However, Loser Engineering sells 35-spline Wavertrac, which is a gear-style limited-slip. We had a Wavertrac in the Crusher for as long as the big-block’s been in it, and we loved it, so we went with another one with the 4.57s.
Gearstar had spee’d our Yank torque converter for cruising rather than drag racing, and the new, lower rear gears and lighter-than-expected vehicle weight conspired to reduce load on the converter and therefore reduced stall speed. Between that and rear brakes that wouldn’t hold power still on the starting line, we’ve got a perfect bench-racing excuse for poor launches. Leaving off idle, our best 60-foot time was 1.57 seconds. It should be better, because by the end of the day at Sacramento Raceways, we’d blasted a 10.07-second quarter-mile pass at 134.8 mph four times in a row immediately before the 10.07 pass. This junk’s a bracket racer! To put the performance in perspective, those passes would make the Crusher very competitive in the Street Race Small-Block Naturally Aspirated class at HOT ROD Drag Week. Of course, that’s assuming it could survive Drag Week.
And it could be quicker. Our biggest problem at the track was programming the transmission to shift as close as possible to the 7,100-rpm rev limit that Horace Mast asked us for based on his experience with the stock-style rocker arms. When ordering 4.57s, we’d assumed the car would cross the line in Third, but it turned out, not being able to shift closer to 7,500-rpm found us needing to grab Overdrive just before the finish line. A 4.30 gear would have been better. That, or simply ignoring Mast’s plea for valve train survival, would have gotten us in the 9s.
OR there’s the guaranteed solution: Holley has already shipped us a NOS Fogger dry nitrous system. That, a new converter, and maybe some 3.73 gears should make us dangerous.
CONCLUSIONS
First, let’s make it clear that this was no apples-to-oranges compare, and that we certainly could have geared and boosted the blown Rat to probably be just as quick as the LS7.Given.
Instead, what’s at stake here is a philosophical dilemma that makes us uneasy about our personal choices. As we wrote earlier, it’s a war of the worlds – one where cars need to look cool and violent and rumpity to go fast, and another where there’s some more sophistication at the cost of style. It’s that simple. The Crusher had far more character and memorable impact with the street-machine look and the giant huffer. With the LS7 and EFI, there’s no denying that every aspect of the car is more drivable. It also hauls ass. But it does so with today’s most predictable engine that doesn’t look anywhere near as cool, and while we haven’t done the exact math, the LS7 and the EFI probably cost $7500 more than the comparative low-buck big-block with is questionable cast crank and stone-and-chisel technology. The LS&’s 100 percent improvement in gas mileage will virtually never make up for that. But the EFI is such an impressive lifestyle change that we’d choose it every time as a fantastic man-toy – if we could afford it.
So what do you pick? Street-machine-style or high-tech performance? We want both, but the call comes down to this: going fast is lookin’ good. And we want to go faster.
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