GEN II SMALL-BLOCK CHEVYGEN II SMALL-BLOCK CHEVY
Identification: The distinctive intake
manifold is a telltale sign of a Gen II engine.
The engine will be stamped on the left-
hand side at the rear of the block just
above the oil filter.
Donor Vehicles: 1992-97 Corvette; 1993-
97 Camaro and Firebird; 1994-96 Impala,
Caprice, Buick Roadmaster, and Cadillac
Fleetwood.
Significant Milestones: 1992-93 had
batch fuel EFI, while 1995 switched to
sequential por t injection. 1996 model s had
significant electronics changes with the
switch to OBD-II. The 1992-97 engines are4WHEELOFFROAD.COM 4-WHEEL & OFF-ROADOCTOBER 2019 15
BUICK V-
Identification: The front-mounted angled
distributor is an easy way to identif y the
Buick 225/231/252 from other GM six-
cylinder engines. The block ID is located on
the back of the block near the bellhousing
mounting boss, or on the lef t side of the block
just below the head. These engines share
the BOP bellhousing bolt pattern with Buick,
Oldsmobile, and Pontiac V-8s and have the
starter motor on the passenger side.
Donor Vehicles: (odd -fire 225) 1964-
67 Buick and Oldsmobile mid-size cars;
1965-71 Jeep CJ and Commando; (odd-fire
231) 1975-1977 and (even-fire 231/252)
1977-1989 various Buick, Oldsmobile, and
Pontiac models.
Significant Milestones: Initially a 225ci
odd-fire engine, the Jeep versions utilized
a much heavier flywheel than the Buick
version to smooth out the vibrations of the
odd-fire engine. GM sold the tooling to Kai-
ser in 1967 but bought it back in 1974. Dis-
placement was increased to 231ci in 1975,
and in mid-1977 the engine was converted
to even-fire. 1982 saw computer-controlled
carburetors and ignition, while throttle-
body injection appeared with some 1984
models. Multiport injection arrived in 1986.
What to Look For: Just about any of
these engines are desirable swap candi-
dates. The 225 is a great choice for any
classic 4x4 but is getting hard to find, while
the later 231 is excellent for just about any
compact application. Stick to rear-wheel-
drive applications, as those are more
likely to be a 231 and not one of the many
derivative V-6 engines that were produced
around the same time. There was also a
higher-displacement 4.1L (252-cube) avail-
able for a few years.
What to Avoid: Stay away from the front-
wheel-drive models. Many of these were
a 3.8L 60-degree engine that share little
in common with the 225/231, including
having a different bellhousing bolt pattern.
While the multiport injection systems are
OK, it’s easier to start with a carbureted
version and just convert it to EFI using any
number of aftermarket EFI systems; many
people report success using a Megasquirt-
based system to inject the odd-fire engines.
Notes: Based off of the 215ci V-8, the
Buick V-6 shares many internal compo-
nents with its V-8 counterparts. With such
a long production run and thanks to so
many variants, the Buck V-6 was one of the
most widely produced engines ever made.BUICK V-valve covers appeared in 1987 along with
throttle-body injection.
What to Look For: It is dif ficult to identif y
the displacement of an SBC externally, and
since all of them interchange, there’s no
guarantee that the engine under the hood
matches the RPO code of the vehicle. The
only definite way to identify the displace-
ment is to decode the ID number on the
block or disassemble the engine. The TBI
versions of this engine are very desirable,
as the injection system is extremely reliable
and the revised valve covers and rear main
seal much better than the earlier versions.
What to Avoid: It’s hard to go wrong with
any small-block Chevy, but there are less
desirable ones. The 267s, 305s, and 307s
were fairly gutless. We’d stay away from
one that appears to have a ton of miles or
significant leaks.
Notes: The Gen I small-block Chevy is the
gold standard for any vehicle enthusiast.
No other engine is more popular or easier
to modify, hence it’s popularity and over-
whelming aftermarket support.GEN I SMALL-BLOCK CHEVY
Identification: the rear-mounted distribu-
tor is one telltale sign of an SBC. The engine
ID number of all small-block Chevys from
1955 to 1995 is located on a flat pad just
ahead of the passenger-side cylinder head.
Donor Vehicles: Dozens of Chevrolet
cars and truck s from 1955 to 1995. If it’s a
gas-burning V-8 and is under the hood of a
Chevrolet, it’s either a big-block or small-
block Chevy.
Significant Milestones: Introduced in
1955 with a 265ci displacement, in 1957
displacement increased to 283ci. The
327engine appeared in 1962, the 302 in
1966, and the 350 in 1967. The 307 came in
1968, the 400 in 1970, and the 305 in 1977.
There was even a 267-cube version aimed
at increasing economy for 1979-1982 GM
A- and G-bodies. The one-piece rear main
seal appeared in 1986, and center boltGEN I SMALL-BLOCK CHEVY