Realistic horsepower for the street
 

I'll say it up front...[size="6"] YOU CAN NEVER HAVE TOO MUCH HORSEPOWER :eek::eek::eek::D.

Now, in real terms, what would you think would be a usable amount of horsepower for a 427 FE in a Cobra, driven on the street in urban areas? :rolleyes:. Thank you for your opinions.

If your just running on the street with no plans to ever race it then IMHO 300hp to 400hp is way more than enough. I had mine built to put out 600hp and I know it's going to get me in trouble in more ways than I can think of.
Don

Urban areas? Forget horsepower for the time being -- horsepower is only a function of your torque value at a given RPM (the higher the RPM the higher the horsepower, even with the same torque). In an urban area you're not going to be winding it out much, but you do want that blast in the back from a strong torque motor. 450 ft/lbs will do you nicely and a good flat torque curve that comes in early and stays flat will make you happier in the city.

Having had and driven all different power levels of the 427s if you just want a fast, reliable car to cruise around in, I wouldn't go over 450 horse. That will get you into trouble in a heartbeat and these cars aren't really heavy. I had one that put out over 500 horse and had it de-tuned down to around 425 horse as it was just to easy to break the tires loose. If you plan to race, that is another story. Also remember that the original Cobras just had 289sand the 427 ones put out about 485 horse, or that was what the competition ones were rated at. The Daytona Coupes which won the Championship had 289s which were rated at around 380/390 horse.
Ok, now all of the high horsepower worshipers can tell me how stupid I am.

Ron :o

My vote is for as much as you can make without getting into exotic parts and specs....like high static compression ratios, huge cams, large port heads, etc. All those seem to take away from the fun if you're just a street driver.

Otherwise, go for broke, as all cars have gas pedals and you don't have to run at WOT if you don't want to.

this is correct, especially if this is your first Cobra.

However, if you build to 500 hp or more, think about a block of wood under the "WOW" pedal until you get used to the car.

400 - 500hp is more than enough, you should never get bored with it, unless you have owned 600 - 700 hp cars weighing 3500 lbs or more before.

E

I agree 400-500hp is more than enough. It is a lot easier getting the HP you want upfront rather than adding on or replacing later.

The original 427 cobras came with 425 hp. That was enough hp to hold the 0-100 mph-0 record for about 20 years.

Abut 5 years ago a Ford F150 Lightning pulled along side me. I dropped into 2nd gear and nailed it. My side-oiler was making awesome noise and the tires were roasting. But, the F150 was right beside me for about 5 or 6 seconds. I backed off for two reasons; embarrassment and fear of getting caught drag racing.:CRY::eek:

My tires were hard Yokohamas. I've since changed over to the Goodyear Billboards.

My engine at the time:
427 with aluminum heads that flow 325 cfm.
Tunnel Wedge intake with a pair of 600 cfm Holleys
Roller rockers
Solid roller cam; 252/262, .633 & .667 lift.
12.0 to 1 compression.
Aluminum flywheel.
4 speed David Kee aluminum Toploader wide-ratio.
3.70 to 1 rear end ratio.

Horsepower is wasted unless you can connect. Obviously I wasn't connecting with the asphalt during the short burst with the F150 mentioned above.:LOL:

I think 450HP is plenty for street. Besides, your FE will have tons of torque.
Keep it a roller Hyd cam, electronic ignition, platinum plugs and you will have no maintainance except oil changes. Leaves more time for driving.
If you can get it to hook up, you'll pretty much rule the street

Mark

600hp+ with a 150 shot of giggle gas for those rare moments..

There's no such thing as too much horse power.. My daily driver @ 3100 lbs puts 509 hp to the tires (dyno'd it a couple weeks ago). My Cobra with anything less than 600 fwhp would be comparatively slower and not satisfying, IMHO.

Dave

It realy depends on what you are going to do with the car. We have all heard that before.

My first cobra a Butler back in 1988 had a 550 HP SO/HR. The car was fun but sucked gas my wife hated to drive it- it was too much and a pain in the but to stay in tune. MOdern stuff of today would be much easier I admit. Today my Kirkham is pretty much a stock 427 SO/LR all iron. Has a huge cam but a perfect-custom carb and MSD ignition. I just did a 1600 mile trip averaged 13mpg with an average speed of 82.3MPH and used four qts of oil with out a wimper. That is what I wanted and I have never been happier and anybody can drive it. Good luck and have fun- it is your artwork I mean investment I mean toy I mean therapy.

What trans and rearend ratio are you looking at?
 

Mdman352 You have not given any other specs on your car. This leaves a larger than normal playing area. For 90% of the people on this forum a good running 390-452 will more than enough power for you to scare the crap out of you in a Cobra.500 ft of torque and 450-475 REAL HP at the rear wheels is about all a cobra can handle in a safe way. Cobra, like others here have said is NOTHING like any other car you have driving. No ABS, No Traction control, No Power Steering in some models, No Power Brakes. %/ I have had a 452 motor in my car for 8 years. 370HP and 460 Ft of torque with a 6K limit for the rpms of this motor. My car would running 12.50 in the 1/4 mile all day long on pilot street tires. The new stroker motor is a 600 torque, 500+ HP motor with the same drive train. I have to change the power band to stop the stupid tire slipping when driving from a stand still. 3.31 gears is too much for this amount of torque. Going to a 3.07. Changing the trans first and second gear to a lower one in the 2.80's. The cam in the motor will also be advanced 2 degrees to remove some bottom end power. FORGET the HP numbers, torque is what moves the car NOT HP. That's for top end running. Build yourself a nice motor with a 550 HP and 600ft of torque with a 6,500 rpm limit and hydro roller valve train. This will give you years of fun and just basic maintainance. Look up Excalipers old threads with that 427 animal he built. He re thought his motor and came up with a streetable motor that was easier to drive, better MPG, could idle for more than 2 minutes, and was just as strong and fast as the race motor. Build yourself a 482 motor with a 630-650 hydro cam shaft and good heads. This is a great build and works in a lite wieght cobra. You will be in the 600 club and still be able to drive the car without the race gas, overheating problems, ear ringing noise, and POLICE CHECK every 2 miles.:eek:%/;):) Rick L. Ps if you want to go racing, build a windsor stroker, cost less to build and break. Cheaper than a FE based motor. Can get the same power you are looking for with a higher rpm range. IMO, I am not a fan of spinning heavy bottom end motors more than 6,500 rpms. FE rod motors run small rod bearings as compared to other cars with the same rotating mass wieght. This is why the stroker kits are running BBC rods, wider bearings to handle the loads.

When is enough enough???
 

The reason for this thread is for informational purposes and to confirm my setup.
I have a Jag rear with 3.55 gears with a Detroit locker. My new motor is a 454 FE with iron heads that have been port matched to the manifold and produces 470 HP and 580 FT. I told the builder I wanted a streetable motor with very little maintenance that I could drive everyday if I wanted to. I am running MT Street Drag radials. My car from a rolling start will spin the tires up to the rev limiter in 1st and about half through 2nd gear but then it gets interesting real quick. :eek::eek:.
I don't know how someone with "regular" tires can get ANY traction. :p
I love the big numbers too but in the real world what good is it if it won't hook????:confused:

Hooking on the street is pointless, unless you were planning on drag racing from stop lights. The added power is seat of the pants feel when punching it from 40 mph. :eek:

Even a Detroit Locker and full slicks are not going to stick with a 2500lb. car, 3.55 rear, and almost 600 ft/lbs of torque. It just ain't gonna happen. You could "de-tune" your engine a little by using a heavier spring to delay the vacuum secondaries a bit, and maybe a tad bit less timing. But what you have is simply "the nature of the beast."

Years ago, maybe the early to mid 90's, not sure, I drove a very early FFR, number 46 or 47.....The owner built it by the manual,stock 225hp 302 GT motor with a 5 speed and 3.55 rear gears....While it was not earth shattering, it had planty of zip and would probably run the quarter mile in the mid 12's,maybe even low 12's, just my guess.....It was plenty fast enough for a novice and made an excellent weekend driver/cruiser car and got about 20+mpg.....would outrun 90% of the cars on the street at that time.......

I think too many people get caught up in the HP #'s game and thing the need 600+ hp to have fun, but those monsters require a lot of mantinance and some are very finicky about running hot in traffic....

Any decent motor with 400hp and 400 lb.ft. of torque will make a fun car to drive on the street and outrun most anything you come up against.....IMHO

Now racing is a whole different ball of wax.......

David

I don't see what the big deal is. My last Cobra was 475 to the ground, but I could see shooting for about 600 to the ground and it still being a nice street car on drag radials. You'd need to beef up the drive line a bit. I guess a 150 shot on my last Cobra would be about right and would put the car in the nines for the 1/4. How fun is that?

Even if you bolted rockets to my roll bars, I could not drive a nine second quarter in my Cobra.:p

Well enough is enough, it's kinda like "Once a King always a King,,Once a K night is enough".

400HP to 500HP is plenty, the sound of that loping FE is the most important part, the torque.....the kick in the back of the head when you get on it! Oh My Godddddd!!!!!!
I can't stand it any longer....pedal to the metal.....OOH ! it felt so good! ......Ahh, now I can relax..I need a smoke.

Wait a while and do it again, Life is good,

Bill