Horsepower in 427 cobra, what is too much? - Page 2

David Kirkham · #21 (**permalink**) 03-21-2010, 05:00 PM

Quote:

Originally Posted by Mark Thompson

I think the lowest power to weight of any sports car was the Porsche 917 which had well over 1000HP in 1300lb and was generally regarded as undriveable. That says you should stay under 2000HP.

David

David Kirkham · #22 (**permalink**) 03-21-2010, 05:04 PM

I guess that really depends on where you live. Here in Utah, we regularly drive up to 9,000 and 10,000 feet. The air gets pretty thin and where you guys have 500 hp down at the beach, we have considerably less in the mountain air. When we drive up Mt. Nebo, there is a very noticeable difference in how far you have to push the gas pedal. The little blocks just lay over on the hills at those altitudes and beg for mercy.

David

jerry mayer · #23 (**permalink**) 03-21-2010, 07:35 PM

Thanks for your input on horsepower. I have always felt in my other toys that I would rather have a lot of power so you don't have to push it hard all the time. rather than wishing that I had more power. I am currently building a 427 cobra with a 600 cubic inch big block ford. We haven't run it yet. This is a street car , but it might run some track days on a road course or so. I probably will never run on the drag strip. I am using a tremic tko 600 extreme and mickey thompson street tires. Ill give a report back in a couple of months.
Thanks for your input. this club has very good info.

Excaliber · #24 (**permalink**) 03-21-2010, 08:35 PM

Do the drag strip!!! I've only done it a few times, just to figure out what all the fuss is about, get an idea of the car's performance and just to have some fun with friends.

Wow, I was impressed, there really is WAY more to it than just "mash the gas". I could feel the addicition, the draw of it coming at me. Not really my cup of tea, but certainly something a guy should do a couple of times. My Cobra buddies and I made a "pact" before hand. No serious racing, no one is there to break anything, let's just go have some fun one Saturday night. Had a ball!!! HAD to go back and do it again!

kobrabytes · #25 (**permalink**) 03-22-2010, 09:56 AM

Keith dyno'd my engine at 699 hp 687 ft lbs of torque.

It seems about right...

The control is all about how you press the peddle...

CobraEd · #26 (**permalink**) 03-22-2010, 10:57 AM

Quote:

Originally Posted by lovehamr

No, but imagine it could be kind of exhilarating!

It's a binary thing. Either ON or OFF !

.

Igofastr · #27 (**permalink**) 03-22-2010, 01:41 PM

I didn't drag my Kirkham, but on the track, my 500ish bhp was NOT enough. BTW, I used my car as a daily driver in the summer months, and driveability was not an issue.

Judging by Maurice's Kirkham, I'd say 600-650 would be about right (a good street-track compromise).

Jamo · #28 (**permalink**) 03-22-2010, 02:05 PM

It's like boobs...you'll know when it's too much.

Streetwize · #29 (**permalink**) 03-28-2010, 05:33 PM

Depends mainly onthe driver, the torque/powerband/gearing you have and how tractible you want the power to roll-on.

600hp generates more Heat than 500hp, to me the best way to build a 600hp motor is to have roughly the same high torque easy revving powerband as a typical 427" 500hp motor with the exception of having an additional 700-1000 rpm up at the very top to where that additional 100hp is there when you need it. With the right heads compression and cam this isn't too hard to do.

I'm also a firm believer in having 2 carbs and tires...a double pumper and race tires for the track and street tires and either a vacuum/Air Valve secondary for the street. Double pumpers (when tweaked for max acceleration) are tough to modulate on the street, especially in a lightweight high powered car and depend on optimum bite....going around a tight corner at speed that looked 'dry'. With a DP it can catch even the most expereinced drivers by suprise when they can't reaquire traction due to lack of tire contact.

427supr · #30 (**permalink**) 03-28-2010, 05:55 PM

I think between 350-450hp is plenty for what most of us use our cars for. I am mainly driving my car on the street. You will rarely use that kind of power on the street. Maybe a short burst here and there. It is a ego thing to say I have 500 or 600 Hp. But it will be rarely utilized. I think alot of the Hp claims people make are exaggerated, until you put your car on a dyno, you will not really know for sure.

Excaliber · #31 (**permalink**) 03-28-2010, 08:11 PM

I live for that "short burst"! Just the other day I was practicing my launch techique, doing hole shots on a remote and deserted highway. Of course I also had to practice "heating the tires up" just before pulling up to the line while I was at it. Couldn't tell for sure how many black marks I left, smoke kept getting in my eyes...

Fordzilla · #32 (**permalink**) 03-28-2010, 09:08 PM

Quote:

Originally Posted by 427supr

I think alot of the Hp claims people make are exaggerated, until you put your car on a dyno, you will not really know for sure.

Yup, & Dynos can be made to read whatever you want them to. A little weight on the waterbrake lever & there you have it, big horsepower numbers!

427supr · #33 (**permalink**) 03-29-2010, 04:59 AM

Owning a cobra is about excess. It is fun to build a motor, and see how much possible HP you can get out of it. Of course within a budget.

CobraEd · #34 (**permalink**) 03-29-2010, 06:21 AM

Quote:

Originally Posted by Fordzilla

Yup, & Dynos can be made to read whatever you want them to. A little weight on the waterbrake lever & there you have it, big horsepower numbers!

We know that a lot of "our" highly reputed engine builders tweek the knobs on their engine dyno for telephone number horsepower readings that are not substantiated on the chassis dyno later.

.