Dynamometer Tells El Camino Owners About Their Engines

CLASSIC LINEUP: Rain didn’t deter 17 hardy El Camino owners from showing up at a spring dust-off that turned into a rinse-away.
CLASSIC LINEUP: Rain didn’t deter 17 hardy El Camino owners from showing up at a spring dust-off that turned into a rinse-away. –BILL GRIFFITH

John Harris knew that spring likely would arrive late this year after our Winter of Discontent. So the retired judge and past director of the National El Camino Owners Association decided to hold the New England region’s Spring Dust Off gathering three weeks later this year, to the last Saturday in April.

So, instead of 2013’s icy gales at Lawrence Airport, the group endured 2014’s cold rain and an “onshore flow’’—coastal New England’s dreaded spring moisture-bearing winds off the ocean.

After breakfast at Jimmy’s Famous Pizza and Miniature Golf in North Andover, the group got a police escort across town as they motored off in caravan to SV Engineering and Performance in Peabody.


Jokes abounded—from “They want to make sure to get us all out of town’’ to “We now know of 17 cars whose owners won’t be able to say their cars have never seen rain or snow’’ to member Leo Janssen of Ashburnham who said, “My wife just told me our windshield leaks!’’

So far, we’re talking a typical cruise night or club gathering; great for folks who share a common interest, in this case the Chevy El Camino and its sister vehicle, the GMC Caballero.

What made this event different was the reception at SV Engineering and Performance and the hands-on demonstration on how a “dyno run’’ can diagnose in a minute what trial-and-error tuning might never accomplish.

Stephen Varney and his superstar assistant, Ashley Barlow, had agreed he would select one El Camino to put on his dyno for a complementary run and then let the members decide which other car would get tested.

Once the members saw what improvements he was accomplishing, the group chipped in to partially sponsor four cars to get tested and, in effect, fine-tuned. Along the way, Varney explained what the readouts meant, among them horsepower, torque, rpm, speedometer, and AFR (air-fuel ratio).


The four cars tested, in order, were:

• Greg and Barb Reynolds’ 1987 El Camino Choo-Choo Custom edition. The Worcester couple’s car still has its original 305-cubic-inch engine with 125,000 miles on the odometer.

• Alexander MacDougall’s 1974 El Camino. The Norwood resident is driving an amazingly rust-free 3rd generation El Camino that he brought in from Arizona with a 454 c.i. engine.

• Dave O’Donnell’s restored 1968 El Camino. The Poland, ME, resident’s car has a rebuilt 327 c.i. engine and has previously won the longest-distance trophy at club events.

• Rick Sender’s 1967 El Camino with his home-rebuilt 454 c.i. engine. Sender, of Kingston, N.H., regularly runs this El Camino at New England Dragway, where he’s lowered his times to 13.4 seconds and 100-101 miles per hour on the quarter mile.

Some of us, including your author, had visions of exploding engines, which made us reluctant to subject our vehicles to this ultimate stress test. Remember, we’re talking about cars that, at minimum, are 25 years old and, at maximum, are 55 years old (El Caminos and their GMC siblings were manufactured from 1959–1987).

Varney, however, said other problems are more likely to happen.

“People build strong engines but don’t always beef up the rest of their drive lines,’’ he says. “We’ve had four drive shafts come apart on the machine. It’s not the universal joints (where the drive shaft attaches to the transmission or rear end) that fail. The stock drive shafts themselves can’t take the power and they just split in half.’’


When asked about his most dramatic incident, he recalled the Honda Accord that had been built out with titanium innards and twin turbos and showed 860 horsepower on the dyno. Unfortunately, it had racing slicks and one came apart, wrapping around the dyno’s drums like a large drive belt. “The machine prefers street tires,’’ he says.

For the record, the highest reading Varney’s seen on his dyno was the 900 horsepower from a 427 small block Chevy with a twin turbo. It’s in a Ferrari-body drag car owned and driven by Ray Pezzi of Chelsea. Varney marvels at the engine and says that car has done 8.65 seconds and 163 miles per hour in the quarter mile.

Our group had more modest results.

The Reynolds’ car was in the 200 horsepower range and declared “in good tune’’ for daily driving.

MacDougall’s 454 produced 288 horsepower, an eye-popping 466 ft.-lb. of torque, and hit 120 miles per hour on the machine.

O’Donnell’s car became the poster child for dyno tuning. Varney spent considerable time adjusting the timing and carburetor settings, boosting the output to 223 horsepower at the rear wheels, which translates to better than 300 horsepower coming out of the engine because the drive train generally loses 30 percent of the power en route to the rear wheels.

Sender told Varney that his El Camino seemed to flatten out in the later stages of its quarter-mile runs, and he wondered if there was a fuel-delivery problem. He had a fuel pressure gauge in the gas line; however, he didn’t have any way to monitor it during his racing runs.

Varney corroborated Sender’s suspicions with just one dyno run. The engine flattened out at 320 horsepower and 409 ft.-lb. of torque, just as Sender described.

“The red line on the computer screen (showing horsepower) should have kept climbing right here,’’ said Varney, pointing to the spot on the graph where horsepower dropped off.

“The fuel pressure gauge dropped to three pounds right at that point,’’ said Sender, who was able to watch his fuel pressure gauge and the computer readout during the test.

“I’d recommend that you add an electric booster pump back by the gas tank,’’ says Varney. “You could put it on a switch so you’d only use it at the track.’’

“Just what I was thinking,’’ said Sender, who is eager to see what the modification will do for his racing times. No doubt that work will be done before the group reconvenes on July 18 for the 6th annual El Camino Night at Lee USA Speedway.

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