By Roger Huntington*
There will always be thousands of car enthusiasts who are never satisfied with
the standard performance you can buy at the showroom. Even when some of the
factories are building out-and-out hot rods -- (which they definitely are these
days) -- they're still not satisfied. They insist on the right to engineer their
own "customized" performance with special speed equipment and modification
procedures that have been the lifeblood of the hot rod sport for 25 years. These
fellows are hopeless hop-up bugs. Sometimes they can't do any better than
factory engineers. I've seen many instances where a modified Super/Stock engine
didn't go any better than a well-tuned stock Super/Stock! But no matter. The
hop-up enthusiast is having a ball -- and there's always the very good chance
that he'll strike on just the right combination that will make a world-beater.
The specialist still has every advantage over the mass-producer.
The purpose of this (article) is to bring you up to date on available special
performance equipment for late Ford Motor Company engines, with some hints on
the application of this equipment and other special procedures to get your best
performance compromise. (And engine modification is always a compromise). I
think it would be best if we considered each basic engine model separately, as
they all have special problems that don't apply to the others. These basic
engines (include) the '54-'57 Ford-Mercury-Thunderbird Y-V8 -- which is still
used as a standard V8 in 292-cubic inch form. Here's a run-down ...
'54-'57 FORD-MERC:
This engine lacks the cubic inch potential of some of our later designs (maximum
stock displacement was 312 inches), but it has plenty of hop-up potential within
its size class. The basic engine was available in stock displacements of 239,
256, 292 and 312 cu. in. All these blocks will take an overbore up to 1/8 except
the 312, which should be limited to 3 7/8 total bore (.075" overbore). The 272
and 292 blocks will take a stroke increase of .340", but the 312 should be held
to 1/4" total stroke increase (to 3.690" total). It is suggested that the
beefier 312 rods be used in all stroked engines. The maximum recommended bore
and stroke on the 312 block (3 7/8 x 3.69") would give 348 cubic inches. That's
the potential.
If you want to increase stroke the best practice is to buy a complete "stroker"
kit, which includes oversize pistons (in any desired bore), rings, pins, rods,
the stroked crank, bearings -- and the whole assembly is dynamically balanced to
a gnat's whisker. This is the only way to go on this. Several big companies
(like Crankshaft Co.) can supply. If you just want to increase the bore there
are any number of California outfits that specialize in pistons for all engines.
Names would include Jahns, JE, Venolia, Forgedtrue, Grant, Thompson, etc. These
special pistons are available in any desired bore size, sized to any desired
clearance, with crown height for any desired stroke -- and you can order them
with special rraised domes to give any desired compression ratio. You can't go
wrong. This is a good way to increase displacement and compression with one
blow.
No other precautions seem necessary in the lower end. Stock copper-lead bearing
shells are strong. Stock oil pressure and capacity are adequate. Bearing
clearances could be increased to .002-.003" for a freer engine if you wish.
Rebalancing the lower end, especially when you change pistons that may have a
slightly different weight, is always a good idea. Piston skirt clearance should
be .003-.007" for the street, but can go to .012 for competition.
Cylinder heads are another area where we can do a lot for the output of this
Ford engine. Fortunately all the heads for these '54-'62 engines are
interchangeable, so we can do a little switching. The '57 heads for the 312
engine had 1.93" intake valves and much larger ports than the earlier heads. The
boys who are really serious generally pick up a set of these heads, then start
modifying from there. Ports are cleaned out a little, matched to the manifold
openings, and generally they will run a 70-degree reamer down into the valve
port (piloted in the guide bore) to open the port diameter out to a seat width
of about 1/16" around the outside edge of the valve. This gives a substantial
increase in breathing area without reducing seat width so much that valve life
is affected. It is also practical to increase the size of the exhaust valve.
Some fellows machine out the seat and port to take the '57 Lincoln exhaust valve
(diameter increase from 1.51 to 1.64"), then chop and regroove the Lincoln stem
to accept the Ford keepers. You can get some crazy breathing out of these heads
with all the tricks.
One special word: Ford heads of this vintage had a considerable amount of
restriction around the edges of the valves caused by the walls of the combustion
chamber being too close -- so they actually shrouded the valve as it opened.
Breathing can be considerably improved by getting in here with a grinder and
cutting away this close restriction around the valves. Of course remember that
any metal you take out of the chamber reduces the compression ratio. This can be
restored by milling a little off the lower head surface. A maximum of .060-inch
can be milled -- though generally .030 is enough to compensate for combustion
chamber "porting". (Incidentally, milling is a cheap way to increase
compression. Keep in mind that a cut of .060-inch raises compression roughly one
full ratio).
Carburetion is one of your toughest problems on a modified engine. You need lots
of venturi area and big manifold passages to minimum restriction at the top end
(for maximum hp) -- but if you go too far you lose a lot of throttle response
and torque at low speed for the street. You have to compromise if you expect to
have a nice drivable street machine. Fortunately there is a terrific variety of
special manifold equipment available for this '54-'57 Ford engine. The factory
has cast iron manifolds to carry a single 2-throat carb, single 4-barrel, or
dual 4-barrels. Edelbrock has an aluminum dual 4-barrel with conventional
"180-degree" passages, three different triple 2-throat manifolds to allow for
the increasing port sizes through the years, plus a 6-carb log manifold (without
heat) for competition. Weiand can supply triple 2-throat and 6-carb logs -- and
Offenhauser has three models of a 3x2 for the different port sizes. Edmunds has
a 3x2 and dual 4-barrel in aluminum. There ought to be enough here to satisfy
any need.
But which carburetion layout to choose for your particular needs? Personally I
like either a single 4-barrel or triple 2-throat system for the street. This
seems to be a good compromise on venturi area between high and low-speed
performance. Ford 4-barrels have the secondary throttles controlled by the
volume of air flow through the primaries, so there is no chance of over
carburetion when you suddenly open the throttle wide at low speed. Even a dual
4-barrel setup with this system isn't bad at the low end. Normally three
2-throat carbs would overcarburate at the low end. But by using one of the new
"progressive" throttle linkages -- where you run on only the center carb up to
about two-thirds throttle, then the end carbs open at a faster rate to full
throttle -- you can get away from a lot of the response and gas mileage
problems. (You still have to be careful about using full throttle at low speeds,
however, as all six barrels will open wide). The 6-carb log manifolds are great
for maximum hp in competition. They're not very suitable for the street, not
only because of the excessive venturi area, but they don't have provision for
exhaust heat to vaporize the fuel in cold weather. If you use your car for both
street and competition, and are willing to put up with a little rougher
operation, they're OK. But don't expect that luxury feel.
Camshafts and valve gear can make or break any high-output engine. It's much
like the problem with carburetion. A long valve open duration (in degrees of
crank rotation) and high valve lift, coupled with very quick opening and closing
rates, are very effective in boosting top-end horsepower. But they also knock
off torque at the low end. Also the high lifts and quick rates can overload your
valve springs at high rpm, cause severe valve "float" that cuts power and ruins
the valve gear. No, you've got to compromise carefully on valve timing, lift and
rates -- then get just the right combination in the valve gear.
You have a lot of equipment to choose from in the specialty market. The big cam
companies like Iskenderian, Howard's, Racer Brown, Engle, Harmon-Collins, etc.,
can supply complete kits that have every part engineered to match in performance
characteristics, to give stable operation at the highest useable rpm. These kits
generally consist of the camshaft itself, with any one of perhaps a dozen
optional grinds -- plus lightweight compatible solid lifters (either flat or
roller type), light tubular pushrods, adjustable rocker arms, with special
high-tension valve springs and heavy-duty spring keepers and locks. The whole
assembly is "tuned" to work as a unit. I can't recommend highly enough that you
spend the extra money and get a complete matched kit. Hot cams used with stock
lifters and springs can often wear lobes in a hurry, float valves at low rpm,
clatter, fail to pull their potential. Don't cut corners.
As to recommendations on specific grinds for specific situations, this is much
too broad a subject to touch here. Your best bet is to outline your car specs to
the cam grinder, tell him what kind of performance you want, how the car will be
used -- and he will give you the optimum grind for the job. As for the problem
of flat-vs.-roller lifters, there seems to be little difference in top power
output. You can use stiffer springs with the rollers, to turn higher rpm,
without wearing out cam lobes -- and they seem to give longer life on the street
for this same reason. Some experts say the reduction of rubbing friction with
roller valve lifters will add 15 to 20 hp to your net output. I don't know. I do
know that roller cams are more expensive than flats ... so you always have to
balance the benefits against the cost.
But I still recommend a complete cam kit rather than a piecemeal conglomeration
of parts when you decide to go modified in this department.
There are a lot of possibilities in special ignition equipment for late Ford
engines. We have the well-known Mallory dual-point distributors, Magspark and
Mini-Mag -- and there are the dual-coil distributors by Jackson, W&H and
Spalding. All have installations for all Ford engines. This is all high-quality
stuff that will do the ignition job under the very toughest conditions. Actually
stock ignition will do the job up to at least 5000 rpm, given the right spark
advance curve. The special ignitions can take it from there -- and, of course,
they all feature custom advance curves that are tailored to a specific
engine-car combination. This is a valuable feature. The optimum advance curve
for dragging on these Ford engines seems to be an initial advance of 12-15
degrees (crank). with full advance of 36-40 degrees at a crank speed of 2000 rpm
or so. Stock mechanisms can be modified to give it.
Superchargers are a very effective way to hop up any engine, since you're
pumping the fuel-air mixture into the cylinder rather than depending on
atmospheric pressure to force it in. As mentioned earlier ... , Ford offered the
Paxton "blower" as optional equipment in 1957 (300 hp); but only a few models
were put out before the AMA anti-horsepower resolution put a stop to it. But
those blown '57 Fords were the hottest things in the Super/Stock class in those
days. Paxton still offers that kit -- and you can still go like that with it.
Add the blower to a few other hop-up goodies like cams, big bores, etc., and
you've got a wild machine. Latham Manufacturing also offers a neat axial-flow
blower kit for the '54-'57 Ford-Merc, driven by a flat belt from a special crank
pulley. This is a larger unit, has a bit more pressure and air flow potential
than the Paxton -- but it costs more. You take your choice. But either one of
them will make your Ford come alive in a way you never thought possible.
No hot engine can really flex its muscles if it can't get rid of the exhaust gas
efficiently. Speed experts used to say we didn't have to worry so much about
exhaust restriction because the gas was being pushed out under 60-100 pounds of
pressure. That's true ... but now we know that we do have to worry about the
restriction even so. It'll kill an engine's performance. Notice the beautiful
streamlined exhaust headers on the late Ford high-performance engines. Ford
engineers have gotten the message. Unfortunately they hadn't received it in the
'54-'57 period -- so you have to depend on the special "California" headers
fabricated from welded steel tubing. The Hedman company can supply a full line
of headers for these cars. They're a must for any all-out combination. Then take
your exhaust back through dual lines. You can use either straight-through steel
or glasspack mufflers or conventional baffle type. The packs have a good sound
and slightly less restriction; but the dual outlet lines themselves cut
back-pressure by 75% -- so you don't sacrifice much performance by using the
quieter baffles.
Do something about your exhaust anyway.
*From the FORD PERFORMANCE HANDBOOK, 1962, by Ray Brock and the Editors of HOT
ROD magazine.
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