The Rescue So Far
When Rollings Automotive checked out Sean Price’s 1965 Nova 350 small-block, it was dead upstairs, held back by a weird cam grind, valvetrain issues, crappy early 1990s TBI iron heads, a messed-up carb, and damaged spark-plug wires. We replaced the cam with a Comp Cams Xtreme Energy XR294H-10 hydraulic roller and Cloyes True-Roller timing set (Oct. 2016 issue), then trash-canned the heads for Brodix Race-Rite 200 aluminum heads and Brodix’s high-rise dual-plane intake (Nov. 2016). This month, we’ll get the carb and ignition up to snuff, sort out some chassis integration issues, and put the Nova back on the chassis dyno.
The Fix: Fuel
Price was running an early Holley 850-cfm double-pumper carb (PN 0-4781-2), but there was what seemed to be a 750-cfm Holley Street HP double-pumper (PN 0-82751) in the trunk. Neither responded to tuning during the original Westech dyno runs, with both down about 20 wheel horsepower (whp) from the best 260-whp baseline garnered with a known-good, 750-cfm shop carb.
To sort out Price’s carbs, we brought in the experts at The Carb Shop, which specializes in everything from straight restorations to full-competition racing carburetors. Based on the Nova’s engine size, mods, and intended use, The Carb Shop’s Randy Robinson chose the 750 as the basis for a “Stage 2” blueprint.
Normally, Stage 2 includes a full refurbishment, truing up all machined surfaces, and custom calibration including jets, power valves, accelerator pump cams, and shooters, plus “secret” internal mods as needed to include idle and high-speed air-bleed changes and PVCR alterations. The goal is a consistent, flat fuel curve from off idle to the top end and is what separates The Carb Shop’s services from simple dial-in tuning.
Price had said the 750 never seemed to run right. No kidding. Turns out, only its main body (with its identifying Street HP List number) was “correct” for the series. Everything else was cobbled together from several different, incompatible carbs-plus, the basic calibration was plain out to lunch. The Carb Shop’s OJ Bretzing found no primary-side power valve (PV) installed. Over-rich primary-side main jets, plus a huge 50cc primary-side accelerator pump, had been installed to try to compensate for the missing PV. “Never block the PV on a street-driven car,” Bretzing explains. “It’s needed for driveability. Without one, if we found the right main jet for WOT [wide-open throttle], part-throttle sucks. If you use the right main jet for part throttle, WOT suffers.” Also needed was a new metering block and throttle blades.
|In addition to these listed values, The Carb Shop also performed undisclosed proprietary air-bleed and PVCR modifications.|
|Main jets||No. 72||No. 82*|
|Needle & seat||0.120″ Viton (both sides)|
|*Leaned to No. 77 during dyno-testing.|
Back at Rollings, the carb was installed atop a Summit phenolic 1-inch-tall open spacer, added for more top-end breathing. Other fuel/air enhancements included a Holley 110-gph high-perf mechanical fuel pump, a better throttle-cable bracket, a raised air-cleaner base, and PCV valve provisions.
The Fix: Spark
Price already had an MSD-6 ignition box, Blaster coil, and MSD billet distributor, but several wires and boots were burned or cracked, and the distributor cap and rotor had seen better days. They were upgraded with new MSD parts, including a universal wire set Rollings custom-tailored for the installation.
The Fix: Front Drives
Cloyes’ Quick Button Two-Piece Timing Cover, with its adjustable cam stop, is said to clear “most” short water pumps, but not the generic short pump on Price’s 350. Rollings used water-pump spacers to gain the necessary clearance, then shimmed and machined the crank and alternator pulleys to restore proper drivebelt alignment.
Back on the Westech Performance chassis dyno running on 91-octane unleaded gas with 38 degrees total advance, The Carb Shop’s metering was virtually spot-on, with only the secondary side requiring slightly leaner jets. Compared to the best baseline run with the known-good shop carb, output improved by more than 133 hp at the wheels-up from the original baseline’s 260 whp at 4,910 rpm to 393.6 whp at 6,019 rpm (a 51-percent improvement). The 12.1–lb-ft torque gain was more modest, with the engine now developing 368.6 lb-ft at 4,929 rpm, up from 356.5 lb-ft at 2,742 rpm. A normally aspirated motor’s torque potential is basically established by its displacement; big cams and heads tend to just raise the rpm at which the peak occurs.
Never in a million years did I expect such an improvement!” – Sean Price
Also par for the course with larger heads and a bigger cam, there were slight losses below 3,000 rpm-about 10 hp and
20 lb-ft-but that’s no big deal on the 1965 Nova with its Tremec five-speed manual trans and 3.73:1-geared 8.8-inch Ford rearend. Driving the car, Price couldn’t believe the change, remarking, “I couldn’t be
At 180–185 psi, the post-rescue cranking compression was now about 15-psi lower than the car’s as-received condition, despite the improvement in static compression ratio from 8.9:1 to 9.5:1, due the Brodix heads’ smaller chambers and a thinner GM head gasket. Cylinder pressures are now right on the sweet spot for aluminum-headed, small-block-Chevy, pump-gas engines.
It’s not rocket science: Stick with known, coordinated parts combos from reputable aftermarket manufacturers. While we all like to save bucks, sometimes trying to save bucks initially ends up costing more in the long run. Expect fit and chassis integration issues with any major upgrade. That’s just hot roddin’!
NEED JUNK FIXED? If your car has a gremlin that just won’t quit, you could be chosen for Hot Rod to the Rescue. Email us at pitstop@HotRod.com and put “Rescue” in the subject line. Include a description of your problem, your location, a photo of the car, and a daytime phone number.
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