With an intercooled supercharger - assuming best means relatively easliy obtainable, straight-forward installation, and affordable. Now, why do you want 400hp and for what? - the dragstrip, the street, etc.?
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I'm back - 2002 GT Convertible, auto: Continental Extreme Contacts, KYB GR-2 shocks/struts, Ford Racing "G" springs, Maximum Motorsports camber plates, 3 pc grill delete, Mach I chin spoiler.
One: Slap on a super charger. All of them should get you to 400hp. I would recomend the saleen unit for reliability ( still a guess, but far less hose connections ) Just make sure you also get a custome tune with a SC
Two: Have the engine removed. Heads ported, bore over, stroked, balanced, all forged internals, shorty headers, CAI, Larger mass Air sensor, larger injectors and a custom dyno tune. This would most likely put you at the 400hp without a SC. ( Then, you could always add an sc later for around 500hp )
If you are 100% sure 400hp is enough, I would slap a Saleen SC on it and get a custome tune....
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2005 Satin Silver GT, auto, with Red leather interior and IUP, Custom painted stripes, Boyd Coddinton Junk Yard Dogs wheels, Saleen S/C, 39lb injectors, 90mm MAF, CAI, JDM SCT Custom Tune ( about 350rwhp )
If you just want hp's for the odd street race why not just a CAI kit, pulleys, reflash, and a 75 hp shot of nitrous. That would by far be the cheapest route and a 75 hp shot would be safe. It should easily give you INXS of 400 hp. Do a careful and neat install of the N2O so if you do by chance blow it up you can just remove the N2O and take it back to the dealer for repair under warranty "I dunno what happened, I just downshifted from 5th to 4th to pass a truck on the highway and it grenaded, I could have been killed, fix this thing immediately" .
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05 Mineral Gray GT Stick
IUP, ICAP, Bullit's With Locks , Alarm, Factory Body Side Mouldings, Shaker 500. Cosmetic mods 23% tint on side glass 32% tint on back. Two 10" black matte Shelby stripes with 1.5 " space.
My Other Ride is Your Mom
Previous Toy's:
86 Z28 with ZZ4/6 speed stick, 80 Trans-Am with anemic 301, 72 Nova SS, LT1 stick car, 67 Cougar anemic 289 auto
Some of you are mixing your HP numbers (fly vs rwhp). Considering the GT is 300 at the fly wheel, getting to 400 at the fly wheel may be possible without a blower if you apply enough performance mods (CAI, headers, x-pipe, tune, 92+ octane, charge motion plates, etc). Procharger quotes 445 at the rear wheel and over 520 at the fly. I have the Procharge installed.
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Silver 2005 Mustang GT
PowerHouse: Turbo & Chassis/Suspension
Fox Lake: Short Block & Heads
Complete Mod List: See my WWW homepage
Some of you are mixing your HP numbers (fly vs rwhp). Considering the GT is 300 at the fly wheel, getting to 400 at the fly wheel may be possible without a blower if you apply enough performance mods (CAI, headers, x-pipe, tune, 92+ octane, charge motion plates, etc). Procharger quotes 445 at the rear wheel and over 520 at the fly. I have the Procharge installed.
Holy crap that's alot of power , can you grab any traction with that kind power and 4:10's? What kind of torque does it produce? At what point does the factory tranny and diff grenade If you get any sort of traction your car must easily dip well into the 11's Im envious sitting here just thinking what it must feel like to have the flesh on your cheeks pulled back to your ears whenever you get on it. I had a 3rd gen Camaro which weighs about the same as an 05 stang with about 400hp at the crank and 3:73's and found that more than adequate for street duty. 520 hp from a little 4.6 litre light weight aluminum blocked engine is just nuts, technology is a wonderful thing
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05 Mineral Gray GT Stick
IUP, ICAP, Bullit's With Locks , Alarm, Factory Body Side Mouldings, Shaker 500. Cosmetic mods 23% tint on side glass 32% tint on back. Two 10" black matte Shelby stripes with 1.5 " space.
My Other Ride is Your Mom
Previous Toy's:
86 Z28 with ZZ4/6 speed stick, 80 Trans-Am with anemic 301, 72 Nova SS, LT1 stick car, 67 Cougar anemic 289 auto
i Have the vortech unit about ready to be installed on mine..How is the drivability on your Procharged car?..have you ran into any issues as of yet?..Is your car a toy mostly or a daily driven car?
It was just installed this week and I plan to pick it up tomorrow (Saturday). We didn't use the ProCharge tune but rather started with the Steeda tune I had on the car already and then used the Steeda tune in conjunction with the ATI tune to get it dialed in just right. The ATI tune was too rich for our liking and we used the ATI tune as a reference only. A good tune is key. The blow installed easy. We replaced the fuel pump with a Walbro High Output Fuel Pump (255LPH)to address issues with the stock fuel pump being maxed out at high rpms. This may not be needed but I didn't want to risk it so it was replaced before it was even on the dyno.
I also had the AutoMeter gauges installed too (boost, a/f ratio & fuel press) on a pillar pod. They look damn good!
The shop I use prefers the loaded dyno set to the weight of the car which provides a more real-world test. The unloaded numbers are what you see advertised on the various manufacture sites. More info here:
Best way to increase stock GT (300HP) to 400HP 
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, can you grab any traction with that kind power and 4:10's? What kind of torque does it produce? At what point does the factory tranny and diff grenade
If you get any sort of traction your car must easily dip well into the 11's
Im envious sitting here just thinking what it must feel like to have the flesh on your cheeks pulled back to your ears whenever you get on it. I had a 3rd gen Camaro which weighs about the same as an 05 stang with about 400hp at the crank and 3:73's and found that more than adequate for street duty. 520 hp from a little 4.6 litre light weight aluminum blocked engine is just nuts, technology is a wonderful thing
