~FLATHEADS~
1. OVERVIEW & HISTORY                7. IGNITION
2. FUEL FLOW                                8. INDUCTION
3. HEADS                                       9. EXHAUST
4. CAMSHAFTS                             10. LUBRICATION     
5.
CRANKSHAFT
6. RODS & PISTONS
OVERVIEW & HISTORY
OK, so to start, just what is a flathead? Well, every time
you go out to start up your Briggs & Stratton lawnmower
engine, you're firing up one. A Flathead is an engine in
which the valve is in the block, not in the head, in what is
called an 'L' configuration or layout. It is one of the
earliest valve configurations for the internal combustion
engine and was favored at the inception of such devices
for its simplicity and lower manufacturing cost. It has to
be pointed out though that by the time the spectacle of
racing had permeated the social conscious, both here in
America and abroad, the OHV (Overhead valve) engine
was king. Conversions for the flathead 4-Cylinder engines
of the early teens were quickly produced for any and all
racing events, often (but not always) leaving their flathead
brothers in the dust. The problem with these early OHV
conversions, as well as the early OEM (Original
Equipment Manufacturers) overhead valve arrangements
was their cost, even though they were available, not
everyone could afford one.
Henry Ford was as much genius as he was visionary. After
two failed attempts in the auto industry, he came up with
his two winners: the assembly line and an affordable
motor car for the masses - the Model T. The assembly line
was to become the model for modern manufacturing;
interchangeable parts greatly reduced the cost of
manufacture allowing nearly all to crank over the “Any
color you want so long as it's black” Model T's. As much as
he wanted to put everyone in America in a car, he also
wanted everyone to be able to enjoy the smooth power of
a V8 engine. In the 1920's these engines were available
only to the privileged who could afford them. They rested
in hulky luxury cars of the time and were often of a
'modular' design, which basically meant that they were
costly to manufacture and maintain. After his successful
run of the Model T was over in 1927, Henry offered the
public his upgrade - the Model A but still used the same
basic flathead 4 engine layout. He then turned his
engineer’s attention to developing an affordable V8 and in
1928 the thrash began. By 1932 the engineering and
tooling of the new flathead V8 was complete and
introduced mid-year to the public. For it's time, it was an
engineering marvel, the intricately cast block is still a
testament to the skill of those who created it. Public
response was fantastic, the engine was a considerable
upgrade over the 4 cylinders of the time, doubling the
horsepower from 40 to 80 and the cars were some of the
fastest of their day. As has been well documented, bank
robbers such as Clyde Barrow and moonshiners preferred
the light Ford cars for their speed and dependability. The
engines remained viable through the 1930's, 1940's and
up until 1953 in America (1954 in Canada, and were also
cast up until approx. 1991 in France for military use).
Which means that there were a lot of these engine cast
and sold. The true death knoll for the Flathead V8 was in
1949 when Cadillac introduced their OHV V8 to the
public, again a sizeable upgrade in power which the
flathead could not match. For the racers and hotrodders
of the 1950's the true end of the Flathead era came in
1955 when Chevrolet introduced it's small block OHV V8.
Virtually the same size and weight with twice the
horsepower, it was the obvious choice to supplant the
faithful flathead, and remains so to this day. For this
discussion though, we're going to concentrate on the
racing flathead of the 1950's and 1960's and the
equipment and modifications which racers applied to the
engine. Specifications, history, technical advice, etc. is
readily available through either books or the web and
we'll provide links to that information for those interested.
Allright - so why a Flathead for the racers of the time?
There are several reasons the first of which is availability.
When first introduced, most racers shunned the engine
in favor of their tried and true 4 bangers with which they
had much experience, and equipment. It's interesting to
point out that later automotive manufacturers like Arthur
and Louis Chevrolet started by making OHV conversions
(in this instance, the Frontenac head) for the Ford 4
bangers. With time though came acceptance of the
Flathead V8 and it's true potential was unlocked by
moonshiners in the south. These moonshiners would
congregate in fields on Sundays to test one another in
front of small crowds, pass the hat for a winners share
and compete. Thus stock car racing was born. Once the
potential of these events was realized by the promoters of
this time and organization came into play, the spectacle of
Stock Car Racing permeated the general public’s
awareness and took off at dusty county horse tracks
across America. It reached upstate NY in approximately
1948 and has been here ever since. By that time, flathead
V8's were more than plentiful and thus cheap. Mechanics
were experienced with them and due to their simple
design; nearly anyone with a set of wrenches could work
on one. Also, due to the ever burgeoning hot rod and
speed trial movements on the West Coast, and the fact
that many young energetic men had returned from the
WWII effort with money in hand and a need for speed, the
sport took off. The West Coast (and California in
particular) offered manufacturing opportunities after the
war effort was complete. Aluminum was again available
and casting techniques had improved immensely. Hot
Rodders and race car owners like Vic Edelbrock, Earl
Evans and Barney Navarro started offering their heads
and intakes that they had proven at the dry lakes and
race tracks, and their businesses took off. In essence, the
Flathead V8 is where it all started for both Hot Rodding
and Stock Car Racing. OK, so those were the advantages
of having a flathead as far as the racers were concerned-
availability of equipment and cost, what were the
disadvantages?     
Ford originally designed the Flathead V8 for everyday
driving and rated their engines at anywhere's from 80 to
115 Hp @ a modest 3600 RPM during its production run.
They were meant to give consumers quick starts,
reasonable power and torque as well as reliability over
their service life. In other words, they weren't designed for
racing and as such had many drawbacks which racers
had to overcome as they tried to coax nearly double the
horsepower out of them in racing trim. The first problem
was the 'L' head valve configuration which creates a
torturous path for the air fuel mixture making it's way
into the combustion chamber. Although a drawback, it's
also one of the flatheads few advantages in that the
mixture is so well atomized by the time it's compressed,
very little ignition lead (as compared to the OHV V8) is
required. The downfall of this arrangement is that it's
more difficult to get the charge into the combustion
chamber than in an overhead valve engine. You've
undoubtedly heard the phrase; “You can't beat cubic
inches” and it's true. More cubic inches equals more fuel -
air mixture which means more power can be created. It's
a bigger bomb. Next problem for the Flathead V8 is
getting the spent charge out. Many have asked us “why
only three exhaust headers?” and the reason is that the
center two cylinders on each bank of the engine share a
siamesed exhaust port. This was most likely done for ease
of casting and cost but it doesn't help in the performance
of the engine. Not only does it create some constipation
but also is a very efficient way of heating up the engine
coolant and all Flathead V8's have a well earned
reputation as boilers. Now, let's look at the bottom end of
the engine and note that the V8 retained its brother 4
banger's crankshaft main layout which equal three. Fine
for 100 horsepower but no comparison to the five mains of
an overhead V8 or the seven of later 6 cylinder engines.
The crankshaft of the Flathead V8 weighs in at a hefty 68
lbs. while the rods are seven inches long and though a
rugged 'I' beam design - they are at best described as
spindly and light (another advantage?). There's more but
that's probably enough for now. So, how did the racers
combat these problems? Mostly by cut and try so let's
look at them one at a time.
Fuel Flow
Flathead or 'L' head valve
arrangement, valve in block.
Harry Miller SOHC (Single
OverHead Cam) conversion
for the Ford Model B engine.
Courtesy of Alan Tatich
Cutaway display of Flathead
Ford V8 engine, this is an
8BA Model, produced from
1949 to 1953.
OverHead Valve
arrangement, valve in head.
Arthur and Louis Chevrolet's
Fronty head for the Ford 4
cylinder engines. Courtesy
of Alan Tatich.
Early Edelbrock decal.
Overhead Valve (left) Vs.
Flathead Valve (right). Note
This guy did a lot of cut and
try, and nearly drove
himself crazy. Courtesy of
Wayne Emm, Nan-Way
Speedshop.