I'm going down the LS1/LS6 route with my Cobra. These motors are used in our local GM cars and the guys down here are getting huge HP out of them with not a lot of work. On a factory slug version LS1 just adding a set of headers a cold air induction and some carefull tuning of the ECU can yield figures of 330HP at the rear wheels.

The bottom end is emensely strong in stock form and there are many blown combinations here reliably making 500 rear wheel horsepower with a stock crank and rods. There was an article I was reading a while back of a local tuning shop trying to find the limit of the bottom end by feeding the motor more and more Nitrous while running it up on the dyno. It got to nearly 700HP before it burnt a valve. On striping it down, the rotating assembly was perfect.

I bought a new crate motor for AU$6750 (US$4800) and there is no way I could build any kind of Ford motor or older generation Chev motor that has the out of the box potential of this motor for that kind of $$$

As for being hard to modify there are a ton of after market parts available now, rods, cranks, cams, heads, manifolds etc. There are guys down here that are boring and slieving the standard LS1 alloy blocks and dropping in stroker cranks to make 422 cubes and bigger.

Cheers

Sorry my first post has to be in a post like this..... but i just had to jump in and lay my $.04 down.

I disagree with quite a few things you say here.

the Al blocks are plenty strong.... here is a stock bottom end with an Incon kit.... how about a 9.85 @ 138.12
and a launch pic just for grins...
http://dieseldigital.net/images/Colu...3/DSC01031.JPG

Here is a custom TT kit.. with an Al Ls6 block, stock crank...
http://harlan-engineering.com/projec...1-1198_IMG.JPG

pictures of the build-up: http://harlan-engineering.com/projectBFT/

he "only" made like 830rwhp/700rwtq on 12psi.... with more tuning and alot more boost.... this thing is gonna be nutts. :JEKYLHYDE

By the way, he is running stock GM HG's and NO o-rings.

and re: the mpg thing... i drive my car everyday i can, on the highway i get 26-28 mpg, around town about 20-23... my car full weight with the old mac mid length headers ran the times in my sig... should be mid 11's now with a good launch and my new mods.
Actually my car is slow compared to most cam'd Ls1's.. heck even compared to the bolt-n class,(stock cam) my car is slow.... alot of the cars are daily drivers and get decent mileage.

Oh.. the clutch comment. I admit, finding a good clutch years ago was hard.... but now it isn't an issue anymore... i have a spec 4 in my car, never slipped a single time and is great on the street.

True my car doesn't make alotta tq... but a friends car does, with the same clutch and no issues.. you might have heard of him:

Check out the tq on this pump gas dyno pull with Ls1 block/heads/crank etc ;)

http://people.maxweb.com/allen/uploads/turbodyno2.jpg

and here are his sites for more pics..

http://community.webshots.com/user/turboformula
http://community.webshots.com/user/mightym0use

And my last comment in this book i just wrote.... i used to be a mustang guy... so i know how the crowd thinks.
After driving/racing/modding the ls1... i will never go back. Nothing i like better than racing heads/cam/power adder 4.6's and whooping up on them.
The '03 mustang is the only mustang that has come out of ford in a long time that is any good...... i still want one :D

There were two versions of a 5.8L DOHC fuel injected motors (based off mustang cobra motors I assume) on display at the Ford Racing booth at PRI today. One was listed to be made in 2004 with 420HP listing for around $20k, and a supercharged version with no release date or specs listed.

This may be a contenter to compete with the base LS6 on power, but not sure about competing on the price, as there were also 500+ HP LS6's on display for around the same price.

There are TWO 5.4's in production, they are NOT the same motor.

The first was the "truck" application, big SUV's etc. That 5.4 was based on the 4.6 technology.

The NEW 5.4 was developed for the new Ford GT(-40). They started with a clean sheet of paper. As fate would have it the bore and stroke were the same as the original 5.4, but thats ALL they have in common!

The new block was designed from the start to be dry sump with unusual casting techniques and oiling system. It was also designed from the start to be super charged. The bottom end is particularly impressive for it's strength.

500 hp at 6,000 rpm with 12 psi boost. 400 Ft. Lbs torque at 2000 rpm!!!!! 500 Ft. Lbs. at 4500 rpm. A torque monster!

The next generation of the NEW 5.4 engine will be modified to accept a wet sump (oil pan) and the engine WILL be used in passenger car applications. A really HOT full size Ford sedan anyone?

Ernie

You know, down the road this going to be like the 351 problem. Is that a 351W or a 351C? Two entirely different motors! I HATE when Ford does that! :D

Ernie,

I think there is even a 3rd version of the 5.4 motor.

Our Aussie Falcons get 2 different 5.4 motors as an option. The first is the same as the truck 5.4 I believe with 3 valve heads. The second is a motor developed by Ford Australia and is a 5.4 with the twin cam 4 valve Cobra R heads. These are installed in the XR8 Falcons and make 260KW (350HP) in base form and 290KW (390HP) in FPV (Ford Performance Vehicles) Trim.

I think this motor has a lot of potential for making good power. The only problem is the size of the thing, It's Huge!!! Ford had to put a huge hood bulge on the XR8 falcons to clear the intake manifold (it actually looks pretty cool). The motor is also very wide, much wider than the regular 5.4 because of the Cobra R heads. The deck height on the 5.4 is greater than the 4.6 Cobra R motor so it realy fills up the engine bay and there isn't much room left around the shock towers. The Falcon front suspension design incorperates a removable cross member because the engine has to be installed from underneath.

I don't think the XR8 5.4 will fit in a Cobra. If you did manage to get one in you would have to narrow the foot boxes so much you wouldn't have room for 3 pedals.

Check out some of the specs on the Aussie 5.4s here Ford Performace Vehicles

Cheers

"The next generation of the NEW 5.4 engine will be modified to accept a wet sump (oil pan) and the engine WILL be used in passenger car applications. A really HOT full size Ford sedan anyone?"

HA!! Not Ford. These are the same guys who ever since cleaning house against the GM F-cars with their 5.0 stang in the very early '90's have been getting their clock cleaned ever since. Yep, the Marauder was "supposed" to be the bomb but was just barely suited to have been Fords competitor to the Impala SS, a car long dead by the time the Marauder. I'd still put my money on the SS in a race. The Marauder is by far better looking though.
If Ford ever offered something again will real balls in the full size line it will probably just barely be quicker and just might handle about as well as the GM's from 10 years past.

Aussie Mike, I wonder if that 5.4 Aussie motor is the "standard" 5.4 souped up with big heads from a 4.6? The base 5.4 CAN be a strong motor WITH some modifications.

The GT 5.4 is in fact DOHC with 4 valves.

SVO460,
So you think Ford would develop a brand new motor for only ONE application, the GT? No way! This new motor WILL find it's way into other Ford products. Lighting Truck perhaps? I'm betting you will see one in a "big" Ford sedan, ala the Chevy Impala SS.

Camaro? Yawn,,,,,, boring!!!

Ernie

I concur with Blykins,,and like wise I am just stating my opinion,,
the new ls1 and 6's are awesome,but remember when your camparing a vette to a cobra your talking highest technology for a push rod motor in a high tech package,,every advantage given for performance and ecomomy,with a cobra is is usually old school ,up dated old school at best,it is definately a purist car.
My opinion is ,if you even begin to have to decide between a vette and the cobra,,you need the vette,,like I tell bike shoppers in my store,if your trying to decide between a harley and another brand,,buy the other brand.
I used have a hard time justifyng spending enough money on a fake cobra to buy a nice c5,but after bing GM at a chevy store for 7 years I stopped feeling that way,after 6 months,the vette is another car at the light and more than likely 15k upside down,the cobra on the other hand is the coolest thing on the road,hands down,but a cushy grocery getter it aint gonna be,and if you turn it into one,youve defeated the whole purpose.
Like Jesse James said,"if it dosent wake up the neighbors kids ,FUC* IT ! "
just my opnion,,but then again I am a seat of the pants kinda guy,,Tk

Excaliber:

Are you sure it was an entirely clean sheet design?

From an article I read they did start with a production block. (I believe aluminum 5.4 lightening engine)

Turned up the boost until it broke. Figured out what broke, fixed it. Turned up the boost some more until it broke, etc.

The article mentioned that it is WAY too expensive for them to make the block just for the GT-40 and was going to all future castings. I believe the main point of failure was the oiling system.

Wish I could remember where I read this. Either way, it's definately not the same engine in a current vehicle.

-steve in nj-

As I understood it they did test the old 5.4 and abandoned it!

The block on the "new" 5.4 is 356-T6 alloy and is machined at Fords Engine Prototype facility. They say this material is 20-30% stronger than the alloy used for the 4.6. A series of ribs across the "valley" above and below add strength. NOTE: The engine is cast with these "ribs" in such a way that there is no open vacuum plenum in the crankcase area. Don't need one, it's a dry sump engine!

Billet steel 4 bolt machined main bearing caps, NOT cast as is typical. On the bottom is a combination cast aluminum bearing cap brace\windage tray. Torque plates on the block are used during the final honing process (unheard of with a production engine)! The block itself has a higher deck height (strength).

The forged steel crank IS "borrowed" from the "old" 5.4 but is re-machined, not interchangable.

The most unusual thing is the top of the connection rod where the wrist pin goes. It is narrow at the top of the hole and wide at the bottom. The only other place I have seen this type of crank\wrist pin thing is in deisel trucks. Whats up with that???

I think to say this is "similiar" to the old 5.4 would be like saying the new LS6 is "kinda like" the old 327-350's. The engines share some "history", but both are now so highly evolved their essentially a "new" motor! Even though the LS6 is STILL AN ANTIQUE push rod motor ( :D I had to get that in).

Ernie

When you say the wrist pin hole, do you mean it's egg shaped?

If so, I know Jaguar did that in one of their engines as a method to remove a harsh natural vibration in the engine.

I must have read an early article on the engine design. We have to remember the GT-40 is moving along FAST. Has any car gone from scratch to production so fast?

-steve in nj-

Wrist pin hole shape in the top of the connecting rod.
 

.

I'm quite confused, but since I'll most likely never have to rebuild a 4.6/5.4/LS1/LS6, I won't think too hard about that connecting rod hole!

-steve in nj-

It's a friction reducing thing. Where the wrist pin goes through the hole. The hole being wide at the bottom gives the connecting rod the same strength as a normal rod would have. With the narrow top, where there is minimal load on the "up stroke" friction is reduced.

Ernie