needed flanges. A simple 4-inch alumi-
num elbow pokes through the hood
skin to exhale spent fumes. Keep the
breathalyzers away, this Monte has
E85 on its breath!
Transaxle: Brandon isn’t the first to
develop an LS-powered, front-drive
Monte Carlo SS, but he is among the
first to replace the factory installed
weak link—the 4T65 transaxle—with
the more robust 4T80E. And just as
the internet has the power to pester
and heckle, it can also build communi-
ties working together to solve common
problems. Here, a Wiki page on Matt
Happel’s Sloppy Mechanics Web page
revealed to Brandon an electrical trick
that makes computer-controlled
4L80E transmissions (RWD style)
behave like a full-manual valvebody for
quick, clean, driver-controlled shifts.
Well, it so happens that the Sloppy
Mechanic’s trick works just as well
on the front-drive 4T80E transaxle.
This allowed Brandon to mount a
sure-shifting B&M Pro Ratchet shifter
in the factory console.
Fuel System: The stock Monte Carlo
fuel tank feeds E85 (108 octane) to
twin Red Horse 340-lb/hr fuel pumps.
Flexible -6AN braided lines feed the
fuel to and from the Edelbrock fuel rails
at 60 to 85 psi, depending on boost.
An Aeromotive regulator monitors fuelTECH NOTES
Who: Brandon Furches
What: 2004 Chevy Monte Carlo SS
Where: Furches Performance;
Ludlow, MA
Engine: Proving the astonishing poten-
tial of turbocharging—and the incredi-
ble strength built into the LS engine
family—the R.A.D. Auto Machine Dyno-
jet 248 chassis dyno registered several
784hp and 718–lb-ft pulls at the front
tires. The source of it is a stock 2006
Monte Carlo SS junkyard engine that
continues to serve without any rebuild-
ing, except for resurfaced “234” heads.
The stock 3.780x3.622-inch bore and
stroke remain, along with the factory-
issue powdered-metal rods and full-
floating pins. The standard bore 10:1
LS4 hypereutectic flat-top pistons
remain, and standard GM MLS-type
head gaskets are used. All block fasten-
ers are standard GM torque-to-yield,
except for ARP 12-point head studs.
The widely praised “234” heads retain
their stock 65cc chambers, 210cc
cathedral-port intake runners, and 75cc
exhaust runners, without porting or
polishing. The stock 2.00-/1.575-inch
GM valves take Brian Tooley Racing
double springs, steel retainers, and
locks. A Comp Cams hydraulic roller
cam and GM LS7 roller lifter set
replaces the stock Monte Carlo SSdisplacement-on-demand equipment.
Cam specs are 0.617/0.617-inch lift,
281/300 degrees duration at 0.006-
inch lift, and 231/248 degrees duration
at 0.050-inch lift. The cam centerline is
111 degrees. Stock LS4 1.7:1-ratio rocker
arms and stands work with Brian
Tooley pushrods. A stock LS4 oil pump
supplies 1.25 ci of Rotella T6 5W40 oil
with every revolution. Stock LS4 valve
covers mount AC Delco coils and NGK
TR18X spark plugs. Ignition timing is
set at 18 degrees total at full boost.
Induction: An Edelbrock Pro-Flo XY
intake manifold was repurposed to
accept the boosted intake charge with
a FAST 92mm Big Mouth throttle-body,
80-pound Ford Racing injectors, and a
Bullseye TCT72 turbocharger. A pair of
Turbosmart 40mm wastegates and a
50mm blow-off valve restrict boost to
24 psi. The entire cold side of the turbo
plumbing was fabricated using 3-inch
aluminum tubing and a Summit Racing
3.5-inch intercooler.
Exhaust: The forward exhaust mani-
fold is a stock LS4 unit with a reworked
flange and 2-inch stainless-steel
V-band. The rearward manifold is from
the passenger side of a 2004 GMC
truck (non EGR) that was massaged to
accept a T304 stainless crossover
tube. Adam Girard’s AG Designs helped
immensely with the fabrication ofI
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The LS4 is the only member of the LS engine family with a single accessory drivebelt. This sheds length and allows transverse fitment
between the strut towers. Chevy built 14,829 LS4 V8-powered Monte Carlos in 2006–2007, plus nearly as many 2006–2009 Impala SSs,
2005–2008 Pontiac Grand Prix GXPs, and 2008 Buick LaCrosse Supers. Donor engines or complete Gen 7 project vehicles are easily found.50 CAR CRAFT AUGUST 2019