Guys who didn’t dig it at first have a least gotten used to it. Our Crusher Camaro’s makeover as a late- ‘70s street machine in the Dec. ’09 issue might have been a bit early for the trend. Maybe the look was a bit more accepted, if not embraced, by the May ’11 issue, wherein we drove the car on a 1,100-mile road trip and suffered only the normal amount of shakedown issues while proving you can drive an 8-71 blown Rat motor virtually anywhere if you set it up right. But, the question remained: How quick is it? Answer: 10.62 at 126 mph in the quarter. Not bad. After posting those numbers on the web and in a YouTube video (“Crusher Camaro Hits the Dragstrip”, HOT ROD Unlimited, episode 3), folks wanted to know the skinny, so here it is.
The ’67 Crusher has been with HOT ROD since 1993 and has seen several makeovers. This time around, the focal point is the engine, which is a 489ci big-block Chevy that’s been around for many years, having seen dyno-test time in HOT ROD, Car Craft, and Chevy High Performance magazines. It’s been so long since we last dyno’d it what we lost all the data after our PC laptop crashed and burned, but we know from old stories that it made 650 to 660 hp at about 6,000 rpm and 650 lb-ft at 4,400. During a chassis-dyno test the day before our road trip, it made 520hp and 500 lb-ft to the Pro Trac tires.
That’s actually not too impressive for a blown Rat but the engine is very, very tame. The cubes come from a 4.280 bore and a 4.250 stroke with Scat cast crank, and the SRP pistons squeeze just 8.95:1 compression. The cam is a weenie Comp Cams hydraulic roller that doesn’t even lope with 224/230 degrees of duration at 0.050, 0.510/0.510 lift and a 100-degree LSA. (Note: Incorrect cam specs were printed in the Dec. ’09 story.) The heads are little Holley oval-ports that have been discontinued but are comparable to Edelbrock Performers. It’s got Hooker’s Darkside black-coated headers with 2.0-inch pipes and 3 ½ inch collectors, and the exhaust is a 3-inch Flowmaster kit with Series 44 mufflers.
Most important, induction comes from a Weiand 8-71 blower that has been Teflon-stripped and blueprinted by The Blower Shop (actually, the shop did that for us twice because we had an ignition problem that led to multiple backfires that totally hashed the rotors). We run the blower significantly underdriven to deliver only 5 psi of boost, and we’ve never run it on higher than 91-octane gas, even at the track.
The best part of the Crusher is the 4L85E auto-overdrive transmission from Gearstar, which modernizes the dinosaur with computer-controlled shift points and adjustable shift firmness. It’s also beefy enough to take as much as 400 hp more than we’re making, so we have room to grow. The transmissions 0.75:1 Fourth gear and lockup converter combine with the 3.50:1 axle gears to deliver 2,100 engine rpm at a 70-mph cruise. The rear axle is a Ford 9-inch with 35-spline axles and a Moser centersection with a Wavetrac limited slip.
Zero rocket science here. In fact, it’s pretty wrong. Out back, we’ve got sagged-out multileaf springs and old-school slapper bars. In the front, it’s all stock but with CPP (PN FCS6330D) big-block Chevelle springs to hoist the nose for an old-school look. We’ve got QA1 double-adjustable shocks all around. In race trim, the car weighed 3,475pounds. Add 175 for the driver and another 20 in video equipment, and you get 3,670 pounds rolling down the track.
AT THE DRAGS
Our private test session at Auto Club Raceway in Fontana, California, was the last one before that track closed due to whiners complaining about the noise. We drove the Crusher 50 miles from home to the track, bolted on some Hoosier 30×9.00-15 radial slicks, and let fly. The first pass, leaving off idle, was 10.702 at 124.98 mph with a 1.574-second 60-foot time. We hot-lapped it to see if heat soak in the blower was going to kill us and hit 10.833 at 124.91. Much of the e.t. was lost up to the 330-foot mark, as we foot-braked some rpm against the converter and spun the tires. But the mph was a repeat, telling us the horsepower was still there.
Tuning ensued. Our FAST air/fuel reader was monitoring O2 sensors in both pipes and telling us we were seeing ratios of around 12.8:1 at the leanest, which made the engine happy and the spark plugs flawless. However Finnegan noted that the timing mark on the ground straps was a little shallow. We were using an MSD Digital 6 Programmable 6AL-2 ignition box, which allowed us to lock out the centrifugal advance mechanism in the distributor and program the timing curve on a laptop with MSD’d Pro-Data software.
We had it tuned for 36 degrees of total timing at cruise and 26 degrees at max boost. Advancing the timing just 1 degree to 37 degrees BTDC had a negative impact, slowing us to a pair of 10.90-second passes at 122-123 mph. But, in a display of remarkable sensitivity to timing, Finnegan finessed it just half a degree, giving us 26.5 degrees total and picked up mph. We also fiddled with shift points, having to click ‘em at 6,000 rpm to avoid valve float. In the end, our best run was the 10.621 at 126 with a 1.564 60-foot and eight-mile performance of 6.76 at 102.57. (Point of interest: To estimate quarter-mile performance based on the eight-mile numbers, many people use a multiplier of 1.56 to 1.6; we use 1.57. Amazing, the Crusher’s 6.767-second eighth-mile number times 1.57 equals 10.624, almost exactly our full track number)
The Crusher’s engine and rear gears are far more optimized for the street and highway than for the track, At 126 mph in Third gear, the big-block is lugging at just 5,200 rpm. Swapping the 3.50 gears for the 4.10s would almost certainly improve the e.t. if we could maintain traction at launch. That’s iffy, because the chassis is far from optimized. The rear springs are sagged to the bumpers on the slapper bars and there’s a little porpoising. The front suspension offers almost no rebound droop to allow optimal body separation at launch, and the car carries 57% of its weight on the nose. The rear end could get better, but we’re not going to be able to solve the front end without losing our ‘70s stance. The front-end alignment could also be a whole lot better, but thanks to that nosebleed posture, we’re out of camber adjustment.
Our other option would be to leave the rear gear as is and simply run more mph to get the finish line rpm closer to the peak How? Swap the blower pulley, make 8 psi of boost, and gain almost 100ho. We’d want to use race gas at that point just to help protect that poor cast crank from possible detonation, but we might even see a 9.99 pass. We have to try it some time. We also have a slick dual-quad plate system from NOS. Hmm. And then there’s that leftover Bonneville short-block at 555ci that would look spiffy under the 8-71. This could go nuts.
Meanwhile, the Crusher remains badass as-is. We can drive it anywhere, it runs cool in traffic, in blazes the meats at will, and people have come on board with the eight track-era shtick. This car’s supposed to be a changeling, morphing styles at our whim. The problem is that we’re pretty well loving it as is. What do you think should be next for this long-term project? Email us: [email protected]