GT40 heads
 

Im looking at these for my 351W.
I don't know anything about this stuff, are these what i want?
How much extra power do you get compared with stock heads?

here is the listing

FORD AU XR8 GT40 CYLINDER HEADS - eBay V8 Engines, Engines, Components, Car Parts, Accessories, Cars, Bikes, Boats. (end time 04-Jul-10 20:27:27 AEST)

Those look to be GT40P cylinder heads. Very nice upgrade from the E7s that are currently on your truck. They have a unique sparkplug angle that makes it difficult to find exhaust manifold/headers that will work with stock exhaust parts.

Here is a good writeup from the FSB forums: GT40P heads AND GT40P HEADERS that WORK

The GT40Ps do flow slightly better than the GT40 in stock form. As far as how much gain they will yield on your 5.8L is anyone's guess. Stock Gen1 Lightnings used GT40 heads and intake as well as factory shorty headers and full dual exhaust. They were rated at ~240HP at the flywheel. With the flow stopper factory intake you have on your 5.8L, stock exhaust and factory tune you might get 20-25HP out of those heads.

Actually the 5.8 intake isn't nearly as much of a cork as some think, but the stock cam on this vintage motor leaves much to be desired. Swap in a Crane 444232 with 1.7 rockers, add the GT40 head and a full exhaust with headers, and the motor will make upwards of 300hp... with the stock truck intake.

Great to know someone knows a good receipe.:-bigparty

Paul, would you have a few graphs from Desktop Dyno to show the torque curves?

CHeers guys, it looks like if i have to buy headers too it puts this mod out of my price range for the moment. I have hooker LT headers at the moment but they cost be $550 to get them out here from the USA.

I dont suppose anyone knows if they will fit?

Not to Highjack your thread. But what did the GT40 Heads come off? Do I need a different intake? If so what about a plenum? Machine work?

Can I use a stock HO cam with this setup? What are the specs the cam?

^ Iron GT-40 heads can be found on 93-95 Cobras, 93-95 Lightning, and early 5.0 Explorers. Later 5.0 Explorers used the GT-40P head. 5.8's also you different sized head bolts compared to the 5.0, so keep that in mind. You can swap heads from a 5.8 to a 5.0 by using a spacer they sell, or 5.0 to 5.8 by have the bolt holes enlarged.

Stock 5.0L HO cam advertised specs are 266°/266° duration, 0.444"/0.444" lift.

^ Per the FRPP webiste:
Ford Racing Performance Parts - [Part Details]

Subscribing.

So did Gt40P or Gt40's ever come on crown vics (cop or standard), mustang 5.0, grand marquis, or cougar's??? Just wondering if that short list of vehicles was the total source list of GT40 heads or if there were a few more... When I go yarding it would be easy enough to start collecting everything I want... Just have to know what to look for.

No.. that is the complete vehicle list for those heads, you could at one time get them through Ford Racing parts but I believe they only sell the aluminum version now.. which perform better but also cost more.

The Stock 5.0L HO cam is SD compatable BTW.

Thanks Paul.

I was recently reading a series of articles at Muscle Mustang and Fast Fords website. The subject was swapping a mild 5.8L engine into a Fox body Mustang. The author purchased a base model 5.8L short block then installed RHS Pro Action 200 heads, Trickflow R-series intake, custom hydraulic roller cam that has similar specs as the Crane 444232, and long tube headers.

The design goal was a smooth idle and good streetable power to ~5500RPM. All the attributes of a good street engine that a truck enthusiast could benefit from. The results were 312 RWHP and 365 ft./lbs of torque. Allowing for a 15% drivetrain power loss that is roughly 360 FWHP.

Here is a graph from the chassis dyno pull:
http://image.musclemustangfastfords....g_gt+graph.jpg

The horsepower graph flattens out around 5000 RPM indicating the cam is mostly likely beyond it's power band. My personal opinion is the TFS R-series intake is way too big for this application, more torque could have been produced under that 5K mark with a less aggressive intake.

Your Desktop Dyno graphs do make a good comparison to the build in these articles. I still question using the stock truck intake, but if you are looking for a budget build of only 300 FWHP run what you have!

Ford Mustang 351 Windsor Engine Replacement Part 1

Ford Mustang 351 Windsor Engine Replacement Part 2

Ford Mustang 351 Windsor Engine Replacement Part 3

This is going to sound like I'm a tool, but I am very dissapointed with those power outputs of the 351. In Australia, ford make an xr8 ute, which is 5.4l and produces 260kw (350hp) and 500nm stock! That is the older model too. THe newer model is 290kw (389hp) and 520nm stock. They use 15L (15.7mpg) petrol per 100km (granted, they do weigh 1700kg). And these cars are $40k brand new. It is frustrating that a 351 with all that extra displacement can't even get those figures when modified. I wish when I had replaced my truck engine a few months ago, I had realized how little power the 351 produced an how inefficient they are on fuel. I wish I had put an xr8 engine in my truck. Maybe next time.

*puts on flame suit*