| GT-40P Heads
[AV] Question: "Does anyone know
the facts about these heads? I keep seeing ads for a complete 5.0
with these heads for less than 2 grand complete! It seems too good
to be true. I've heard that the gt40p heads performed well but had
spark plug & header fitment problems. Any one out there know for
sure if they'll work with the FFR "L-R header flip"
exhaust system?
The motor I've seen in the mags is a complete
longblock 5.0 with choice of a e-303 or b303 cam and the gt40p heads
for 1895.00. I'm thinking this motor with a Roadster intake, roller
rockers,70mm TB,pro-m air sensor,24lph injectors, etc=fairly cheap
decent HP."
Answers and Opinions:
[SD] "I picked up an explorer 5.0 engine,
it has the gt-40p heads. The angle on the spark plugs is more
straight into the piston, I am running mac unequal length headers
and they work fine in the ffr. I was told the only downfall to this
setup is that after 1994 the 5.0 engines did not take power adders
very well, the composite pistons were melting! One mustang guy I
talked to said the a blower with mild boost was about all it could
take."
[JP] "what size valves come with these?
1.84/1.45 Is stock I believe but not sure."
[Buzz] "I just installed GT40-P heads.
Everything hooked up fine, had to ping one header tube and use right
angle plug boots. I also did a mild port and polish of the bowls and
runners as well as matched GT40 intake to the heads. Topped this off
with F-303 and 1.6 rollers 65mm TB and spacer and engine pulls like
a monster into the 6000 rpm range. I still have the 273 gear and the
engine does just fine. The 1.45 exhaust helps improve low range
power in the Explorer and seems to work well with my mods and 273
gear."
[DD] "
AFTER SOME ADVICE ON AN EARLIER POSTING I FOUND A
COPY OF THE JAN 1998 MUSCLE MUSTANGS AND FAST FORDS. THEY DESCRIBED
THE ENGINE AND HEADS COMPLETELY. THE BOTTOM OF THE ENGINE IS
THE SAME AS THE Roadster ENGINES PISTONS AND ALL. 1996-1997 1/4 ARE
8.6:1 AND 1997 1/4 UP ARE 9.0:1 COMPRESSION RATIOS. THE COMPOSITE
PIECES ARE THE Roadster STYLE MASTIC LAYER VALVES LAMINATED TO DAMPEN
VALVE NOISE. THESE VALVES ARE SUPPOSED TO BE GOOD. THE LIMITING
FACTOR IN THESE ENGINES IS SAID TO BE TO THE EXHAUST VALVE SIZE
(1.46 ON 1997 AND UP ENGINES) . DURING HIGH FLOW/RPM SITUATIONS.
INTAKES ARE 1.84 BUT AT SPEEDS1500-5500 RPM THE HEADS ARE MORE
EFFICIENT AND CREATE MORE HP AND TORQUE THAN THE GT-40 REGULAR HEADS
FOUND ON THE 1996 EXPLORERS. THE BIG DIFFERENCE IN THESE HEADS IS
THAT FOR THE FIRST TIME IN 35 YEARS OF FORD SMALL BLOCK HEADS THEY
MOVE THE PLUG CLOSER BETWEEN THE VALVES. THIS RESULTED IN BETTER
FUEL MIXTURE AND REFINED COMBUSTION STABILITY. THE GT40P HEADS ALSO
HAVE SLIGHTLY SMALLER COMBUSTION CHAMBERS 58.3-61.3CC COMPARED TO
63.4-66.4CC IN PREVIOUS GT40 HEADS BUMPING UP THE COMPRESSION. THE
EXPLORER MOTORS COME WITH STAMPED 1.6 ROCKERS AND A F4TE6250-BA CAM
(.264" INT/.280" EXH. WITH 256 AND 266 ENDURANCE). WITH A
CHANGE TO THE CAM AND I.7 ROCKER ARMS THEY SAY THESE MOTORS PULL
HARD IN A 3300 POUND MUSTANG. I DON'T KNOW IF THAT'S WHAT WE WANT
FOR A 2200 POUND CAR BUT THAT'S WHAT I'M GOING TO TRY SINCE I
ALREADY BOUGHT ONE.
IF ANY ONE IS INTERESTED IN THE REST OF THE
ENGINE. THE 65MM THROTTLE BODY CAME FROM THE 5.8 LITER LIGHTNING
MOTOR WITH A SMALL CHANGE TO THE LINKAGE. THE INTAKE MANIFOLD IS
VERY SIMILAR TO A GT-40 BUT HAS LONGER TAPERED TUBESTO MAINTAIN FLOW
VELOCITIES AND TORQUE. THIS INTAKE IS IS SUPPOSED TO FLOW BETTER
THAN THE ORIGINAL GT40 INTAKE DUE TO REVISIONS TO THE RUNNER RADII
AND RECONFIGURED PORT FLOOR. THERE IS A LOT MORE BUT I'M TIRED
TYPING. JUST ASK QUESTIONS AND I WILL TRY TO ANSWER THEM.
FORD SAID THESE WERE THE LAST IMPROVEMENTS
THEY MADE ON THE 5.0 AND HAD NO MUSCLE CAR TO PUT THEM IN SINCE
CHANGING TO 4.6L IN THE STANG. NOW I'M DONE."
FORD SAYS THEY ARE SLATED TO USE THIS MOTOR
UNTIL 2001 IN EXPLORERS AND MOUNTAINEERS. THAT MIGHT BE THE BEST LOW
MILEAGE SOURCE FOR 5.0S IN THE YEARS TO COME.
[RF] "Along with owning the best bang for
the buck Roadster I think this Explorer intake and GT40p head setup is
the way to go. I read Super Ford and 5.0 and follow all the intake,
head and cam articles for info. It makes sense to use these Ford
parts if one is happy with a 300+hp driver Roadster."
[SD] "I went with the 96 explorer engine,
with a accel distributor, I kept the same cam in and it seems to
pull the car really well! I've only got about 120 miles on the
engine, so I've been taking it easy."\
[DS] "5.0 Mag recently (July '99 issue)
did a special tech issue (not the normal monthly mag) and there was
an article on HP gain from some bolt on items. They wanted to use a
new SVO crate motor but due to availability ended up using a new
Explorer motor. The results were interesting.
They wanted to compare stock numbers of a
normal 5.0 so they didn't use the GT40P heads. All numbers are
without accessories and 14 degrees initial timing. With a pair of
slightly modified 5.0 heads, a 65 mm TB, 73 mm Mass air, Roadster upper
and lower (which, incidentally have almost identical flow characteristics
as the Explorer) and stock cam the engine pulled 300 HP and 349
lb/feet of torque.
With the GT40 X heads (Aluminum) the engine
went to 325 HP and 358 lb/ft.
With an E303 cam the numbers were 345 HP and
360 lb/ft.
Too bad they didn't use the heads, but with an
e cam and the rest of the stock Explorer set up, the number have to
exceed 300 HP with accessories at the flywheel."
[G] "I also am going the Explorer route.
Talked with Gordon Levy and he said the 4 into 4 FFR headers will
fit fine. You just have to route the sparkplug wires underneath."
[AV] "I'm using the MAC "P"
headers (had them coated by airborne coatings) & they fit fine
on my FFR. The mac "P" headers were around 200 bucks I
think."
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