Have I maximized output?

[needtobuy]

I have newer FIA by Unique with 450 HP Ford crate motor (347), Tremec 600, Jag IRS rear, Edlebrock Pro flow I & Paxton supercharger (boost @ 4.5lb.). Rear wheel dyno is 520 HP & torque @ 485 (6,200 RPM). I don't race it or work it hard, just punch from a roll now & then.

I have been told by some sharp guys @ performance shops that I have maximized the components & that I cannot reliably get more power out the rear wheels. Others have said that given the use it gets I can get 600HP out the rear wheels with no major concerns. My understanding is that I will need to upgrade the injectors to keep the fuel air ratio in check. Not sure if the tranny can handle the additional torque though. I would appreciate any technical &/ or philosophical thoughts. I just don't want to start pushing components too hard & spend lots of money on upgrades. Also please don't tell me I don't need the extra power...none of us needs a Cobra either, right! We just like the things. Thanks for the help.

LH

[AL427SBF]

You don't need the extra power.

[RICK LAKE]

needtobuy LH 600 hp is not out of the question but things like having enough fuel supply, strong fuel pump, running a careful timing setup. You also should look into a Snow water/methanol injection system to pervent and cool the combustion temps. EGT gauge would also be a good idea.
A good blow off valve to help control boost. You didn't say which Paxton blower you are running, If it's a ball bearing setup, this is a safe one to stop blower pressure from banging the impellor when going from full boost to closing the throttle plate. The pressure has no where to go and bangs the blower. Ball bearing blower are less effected than gear drivin ones. You are going to need about 9-10 psi for 600 hp or torque. The stock injectors will be running about a 90% duty cycle, This is hard on them. Should go to the 42pound injectors with the same ohm range as what is in the car and have the motor recalibrated on a chassic dyno. Hi test gas and booster wouldn't hurt either. Make sure the O2 sensors are not effected by lead additives.
Last note, run the motor a little soft on the A/F ratio and keep the timing down to 2 degrees less with each pound of boost added to the motor.
I wouldn't keep pounding on this motor, roll on and off the gas. You may want to look at the exhaust system first for restriction of the motor if you are running side pipes with mufflers inside. This can cause you 10-60 HP alone. Good luck This should get you in the high 500's. Trans should be OK as long as no 3,000 rpm clutch drops to the drive train on soft tires. Rick L. Ps I don't know what kind of work was done to the Jag rearend but they are rated at 450/450 with 27 spline axles. CWI sells a 30 spline kit for the 600/600 club. I have seen 27 and 19 spline axles twist with good power and sticky tires. That carrier is only a Dana 44. Adding a support carrier cover to help control the caps for the rearend is also a good idea. LWP sells them. Been runing one for 13 years, no failures with the 30 spline setup and a locker inside. Rick

[blykins]

If it's a production block, then all the other stuff doesn't matter. A factory block just won't take that kind of horsepower for long....even with the fancy main stud girdles, valley girdles, etc, etc.

[needtobuy]

Greatly appreciate the posts & the time spent. fantastic info, some over my head a little. I think "AL427SBF" actually got it right...."don't need the extra power". Sounds like a can of worms that gets pricey for a checkbook mechanic, or could ruin a great motor. Answers to Q&A:

> Ford Racing Crate Motor with Aluminum "Z" heads motor model M-6007- C347. The guys @ the dealership who ordered the motor for the original owner said it could hold over 700HP with no trouble, but that's all I know.

> Paxton NOVI "SL". I understand that this design takes care of the back pressure generated, but that was just my interpretation of the literature. The dyno guys said that the back pressure can also be vented back into manifold just in case- I may not have provided the precise wording here.

The guys @ Unique also said the rear end could handle well over 700HP flywheel) with no problem, but you never really know who you are talking to.

All in all there are enough what if's that I think I will leave it alone. Runs great with no issues.

Again, my first time on the technical blog- good results. I did find the car in the "for sale"" section last August.

Thanks again for the help & any additional thoughts....One more thing... thoughts on a soft top? I hear they are junk, but in CO there area lot so pretty good driving days in the winter. I understand the rigid canvas tops are workable?

Thanks,

LH

[blykins]

Originally Posted by needtobuy

> Ford Racing Crate Motor with Aluminum "Z" heads motor model M-6007- C347. The guys @ the dealership who ordered the motor for the original owner said it could hold over 700HP with no trouble, but that's all I know.LH

Salesmen....very good at lying.

I can show you some pictures of some 302 blocks that have split in half at around the 550hp (flywheel, not rear wheel) mark. With the girdle still holding the main caps together.

[needtobuy]

I would not be on a blog if I had thin skin- no problem. Sounds like a good place to leave the motor. Don't want cooked pistons, split block or busted rear end. Excellent advice from all. Very please with the Cobra (albeit a replica). I was a Vette guy many years & got tired of hearing about the Cobras. Even the mild ones beat about anything else around. Re: "Zoom This": my first choice was a stroked 351 like the 418, I just did not find one in the price range I needed.

Thanks to all for the help. Any thoughts on the soft top?

Thanks
LH

[blykins]

I didn't mean to come across crass, and I apologize if I did.....but just trying to stress very strongly that the production blocks weren't made for that kind of power.

It seriously yanks my chain when plainly dishonest people take advantage of people wanting to spend hard earned money.

[AL427SBF]

I think "AL427SBF" actually got it right...."don't need the extra power".

That was my smart ass remark to your Also please don't tell me I don't need the extra power...

It seems more often than not, when you take an already BUILT race motor and try to squeeze another ~35% out of it, inevitably you will run into that can-o-worms RICK LAKE pointed out, and with the blykins catastrophic failure always pending. Drive it like there's an egg under the gas peddle and you might get away with it,

Of course The guys @ the dealership who ordered the motor for the original owner said it could hold over 700HP with no trouble, but remember they are are out of $$ and holding a loss until they sell it.

You've already got a kick ass motor, and with some margin to driver it hard - enjoy

[Zoom This]

No matter how right you get it up top with injectors, timing etc., it's the bottom end that has to be tough enough to take 600+ HP. You'll need an aftermarket magnafluxed block, a good forged crank, H-beam rods and hi-end forged pistons. Then, work the heads for maximum pressure sealing (O-rings?) for over the top HP. Hell, my 418W with 478 RWHP is one jumpy sports car on an open road. Enjoy what you have unless you're going to campaign the car at the drag strip.

[needtobuy]

Will do.

Thanks,
LH

[Sminor]

Needtobuy, I saw a green Cobra with yellow stripes in Lyons, Colorado last week. Would that be yours?
steve

[needtobuy]

Steve,

I am red stripes on silver, but I think I saw that one @ the NC Mustang show in July (Loveland). The sign said "a real cobra", but it had a Rousch 427 & lots of modern goodies. It looked like a Superformance. I don;t think anyone would just park an original out in a parking lot without a rope & the owner sitting in a lawn chair.

What do you drive?

Thanks,

LH

[Sminor]

Needtobuy, I drive a Shell Valley roadster, blue with white stripes. I was in Boulder visiting the Shelby American Museum (among other things). Beautiful country out there and wonderful people. I'll definately be back.
steve

[needtobuy]

I hear good things about the Shell Valley cars. That museum is right on my business travel route. I need to check it out.

Thx,

Lewis