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Jim Moran's 1970 Chevy Chevelle - Quietus

Jim Moran's Twin-Turbo '70 Chevelle

By Mike Yoksich, Photography by Mike Yoksich

Tech Notes
Who: Jim Moran
What: '70 Chevrolet Chevelle
Where: Round Lake, Illinois: It's cold there right now.

Engine: The motor was scored from a guy who said it came out of a wrecked Escalade. Jim wasn't even sure how many miles it had on it. He did know that the heads had never been off the motor and it was completely stock. He added a cam designed for the factory '02 LS6/Z06 Corvette, a set of Comp pushrods, and Patriot gold valve-springs. He also swapped the pan for one from an F-body Camaro before painting the thing Chevy orange and dropping it into the engine bay. The intake is an Edelbrock Pro Flow XT that uses the stock LS1 throttle-body and 60-lb/hr Siemens injectors. The mass air meter was eliminated when the engine was converted to a speed density system. The stock LS1 computer was tuned using an HPTuners custom operating system. The ignition uses stock LS1 coils connected to an MSD two-step. Jim activates the rev limiter using the horn button and leaves the line at 2,200 to 2,300 rpm.

Turbos: Jim flipped and modified the LQ9 truck manifolds to mate with the Precision TA5557 turbos. He also hand-fabbed the air-to-water intercooler using a Garrett/Honeywell core and used the vintage cooler in the trunk as a reservoir.

Exhaust: Jim fabricated the front half of the exhaust system and plumbed it into a 2.5-inch stainless-steel system from Pypes. For the quiet sleeper sound, Jim uses a set of Pypes Race Pro mufflers.

Differential: Jim pulled the stock 8.2-inch 10-bolt and wisely upgraded it to a 12-bolt with a 3.31:1 ratio, a GM limited slip, and a 3.5-inch aluminum driveshaft.

Fuel system: The fuel system for Jim's Chevelle consists of a Walbro 255-gph in-tank fuel pump, a KB Boost-A-Pump, and the car's stock 5/16-inch fuel feed line.

Goodies: Jim's super-sleeper Chevelle was going to be his seasonal daily driver, so he didn't want to lose the air conditioning in his ride. The stock LQ9 truck air conditioning compressor was mounted on the lower right side of the engine. He pieced together the lines from used parts and installed a recalibrated R134a POA valve from Classic Auto Air. The rest of the stock A/C system was flushed and reassembled. Jim built the air-to-water intercooler to mount between the engine and the factory dual-core radiator so he could keep the stock A/C condenser in the original location. The system blows 33 degrees at the vents and makes the car a pleasure to drive during the summer. The Chevelle never gets hotter than 190 degrees, even on a 90-degree day with the air conditioning on.

Interior: You can't sneak up on people without a completely stock interior in a funky gold color with supercool clear floor mats.

Suspension: The suspension is stock with Monroe shocks and Airlift bags in the rear. Jim went through the suspension, adding new bushings in all the pivot points and making sure everything was straight and solid. The brakes are the original drums, front and rear. The drums have been able to stop the car at the strip from 130 mph, but Jim's going to get disc brakes as soon as his budget allows.

Transmission: The transmission for Jim's Chevelle had to be pretty stout. He went with a GM 4L65E four-speed overdrive modified by Finish Line Transmissions in Wood Dale, Illinois. In addition to including a heavy-duty version of nearly every moving part in the trans, the converter was restalled to 2,600 rpm, which seems to be the magic number for most street/strip turbo applications. Jim had to cut the bracket off of the crossmember for the trans mount, move it back, and flip it upside down to get the trans to fit. He also had to shorten the driveshaft.

Wheels/Tires: Being a sleeper meant 15x7 steel wheels with poverty caps. Seeking traction for the Chevelle and not wanting to use big slicks, Jim had a set of Mickey Thompson 235/60-15 ET Street Radials modified by Diamond-back Tires to look granny-approved with 3/8-inch whitewalls.

By Mike Yoksich
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