16 OCTOBER 20194-WHEEL & OFF-ROAD 4WHEELOFFROAD.COM
JUNKYARD ENGINE SPOTTER’S GUIDE
referred to as LT1s. A high-performance
LT4 appeared in 1996 in Cor vettes and
1997 in Camaros and Firebirds.
What to Look For: Any of these engines
are desirable, so focus on finding one that
appears to be well cared for and hasn’t
been raced to oblivion.
What to Avoid: The early batch-fire sys-
tems are not very efficient and are not well
supported by the aftermarket due to their
brief production run. These early engines
were also plagued with a problematic
Opti-Spark distributor. Because these
engines were in performance cars, many
of them led a rough life at the dragstrip
and at the track, so buyer beware.
Notes: Wedged in between the long
production run of the Gen I small-block
and the wildly popular Gen III LS that came
later, the relatively short production
run and limited use of the Gen II engines
means they are often overlooked by both
vehicle builders and the aftermarket.
Though they produce respectable power,
there are better choices available.GEN III/IV SMALL-BLOCK CHEVY
Identification: Coil packs mounted on
the valve cover are a distinctive feature of
LS engines. The eighth spot in the VIN will
identify exactly which version of the LS
engine is under the hood. The engine dis-
placement will be cast into the back of the
block just under the head. In the case of the
4.8L/5.3L, the head casting numbers may
help narrow down identity. Summit Racing
Equipment has a pretty good interactive LS
identification tool at bit.ly/31iEgo1.
Donor Vehicles: 1998-2012 Corvette;
1999-2012 GM trucks.
Significant Milestones: Gen III engines
were introduced in the Corvette in 1997
and the Camaro/Firebird in 1998, and
arrived in trucks in 1999. Many different ver-
sions of this engine were introduced, and
each has its own reference. Gen IV engines
appeared in 2005, and while the same in
many ways, Gen IV engines have things
like active fuel management (AFM, alsosometimes referred to as displacement on
demand) and variable valve timing (VVT).
What to Look For: Just about any LS
engine is a viable swap candidate. The
high-performance LS1 and LS6 are desir-
able but command high prices, as do the
6.0L LQ4 and LQ9 engines. There were
aluminum-block variants of the LS that
are desirable for lightweight applications.
The 4.8L engines are often overlooked due
to their small displacement, but as a result
they are usually inexpensive compared to
other LS engines.
What to Avoid: The LS4 is one variant
of the LS engine family that was used in
front-wheel-drive cars like the Impala SS
and Pontiac Grand Prix. There are many
differences between this engine and the
rest of the LS engine family, making them
a nightmare to work with; they are there-
fore best avoided. The engine manage-
ment systems are quite a bit more compli-
cated on Gen IV engines, so if simple is a
priority, stick with a Gen III engine.
Notes: The LS engine is the Gen I small-
block Chevy of the 21st century. These
engines make amazing amounts of power,
are as reliable as a hammer, and can last
hundreds of thousands of miles with
proper care. They also have tremendous
aftermarket support.GEN III/IV SMALL-BLOCK CHEVYFORD
SMALL-BLOCK FORD
Identification: Six-bolt valve covers are
one surefire way to identify popular small-
block Ford engines. The thermostat hous-
ing is on the intake manifold. Narrowing
down the identification requires locating
the ID tag, which is a piece of aluminum
about 3 inches long and half an inch wide.
You can also obtain some information with
the block casting numbers, which will be
cast into the block on one side or the other.
Donor Vehicles: Numerous 1963-
Ford cars and trucks.Significant Milestones: Introduced as a
289 in 1963, the displacement increased
to 302 in 1968. The 351W was introduced
in 1969 and shares many of the same
attributes as the 302. The 302 H.O. is intro-
duced in 1982 in Mustangs. Fuel injection
arrived for both engines in 1986. Quite a
few block and head changes took place
throughout the production run of the
engines. These engines all have a Ford
small-block bolt pattern, but there was a
small-block pattern change in 1966.
What to Look For: Like many other
engine families, horsepower outputs vary
throughout production but were lowest
in the mid to late 1970s, so staying away
from those years isn’t a bad idea. Many
of the carbureted engines came with the
Motorcraft 2100, which is an excellent
off-road carburetor. If you’re looking for a
fuel-injected small-block in a truck, stick
with 1992 and later.
What to Avoid: A 255ci small-block
used from 1980 to 1982 in several Ford
cars and F-series trucks was an absolute
turd. Many of the early fuel-injected trucks
used an inefficient batch-fire system rath-
er than a sequential-port injection system
Notes: This engine family enjoyed a
long production run and was used in a
variety of Ford cars and trucks, making
them cheap and plentiful. Though the EFI
systems have been adapted successfully
in non-Ford vehicles, there isn’t the same
level of aftermarket support as Chevy
platforms of the same era.SMALL-BLOCK FORD351M/
Identification: Look for eight bolts on
rectangular valve covers, and the ther-
mostat housing is on the block. The block
casting numbers are located near the bell-
housing on the passenger side.
Donor Vehicles: Various 1970-
Ford cars and 1970-1982 Ford trucks.
Significant Milestones: The 351M
replaced the 351C in passenger cars in- Ford trucks were never offered with
351M/