Dalthius

I talked to somebody a bit ago about switching out the heads of my 03 GT with the heads from a 99' or earlier Ford Explorer, GT40 heads or something. I'm not seeing much on the net about it, but haven't looked too hard. How feasable is this? The guy is saying he saw a 40hp increase (I'm assuming from the flywheel, didn't ask). I know you have to get the valve covers, too, so the dipstick/etc matches up.

Any comments? I could likely get the heads from a junkyard pretty cheap...

02StanGT

You wouldn't have any cams if you switched to those Explorer heads. Those years were 5.0's. I think your guy if f'in with you. GT-40 heads are 5.0 heads.

ReVz

What years did the explorers start getting those heads?

badtzmaru

Those years on an explorer are 5.0
Good luck with your 4.6l

02StanGT

I'm not sure they did. I was under the impression GT-40 was Ford's "aftermarket" heads for the 5.0.

badtzmaru

I hope you find this info useful. Good luck.

FFRCOBRA.com

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 COBRA 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 COBRA 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 Cobra 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 Cobra."

[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, Cobra 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."

badtzmaru

sorry, it is kinda long.

ReVz

so wait what year explorers were these again? im still lost and confused

Dalthius

Hmpf....this guy was pretty hard core about it. Oh, uh, I neglected to mention he's driving an old Fox 5.0, lol, but he also talked about a way to get the Explorer heads to fit on my 4.6. I forgot how he said to do it...I'll have to ask him again.

FWP!

Getting push rod heads to fit on a block that doesn't have alleys for the rods and is designed for a pair of timing chains and cams would be quite a feat.

GT40 heads are for 5.0's only, which are a pushrod V8.