Various questions from a new guy who appreciates whatever help might be offered.

[littlewave]

Hey fellas. ? Wondering if 425 h.p. is enough? Just going to be a weekender and maybe a few 1/4 passes. Seems like alot of people on here are at 500+ any advice would be appreciated.

[vector1]

our club just did a dyno session, most of the cars were 285-335 at the rear wheels, nothing exotic, but i didn't see too many people disappointed!

[littlewave]

thanks vector1. How bout this ? If I have 425 at the flywheel,how much rear wheel hp would I have? t5 wc tranny 9" with 3.50 gears with 275 50 15s approx. of course.

[marcocsx3121]

Assuming the usual 15% drive line loss, you're around 360 at the wheels.

[vector1]

probably about as much as the t5 will handle. i would guess around 300 at the rear wheels. there was a guy there who probably had something similiar to your 351 and comparing it to my 351 which is rated at 385 he put down 330 range at the wheels, and my car is pleasant to drive. it's all dyno magic btw, only good for tuning or comparing two cars on the same dyno or under same conditions with similiar dyno setup.

[littlewave]

marcocsx, I sold my 69 vette to build my Cobra. Love 2 seaters, but Cobra is tops on my list!

[fordracing65]

You have plenty of power, it's a power to weight game and cobras weight nothing, there is such a thing of having to much power, your cars power is a balanced car, which is the way to build one.

[RICK LAKE]

littlewave This is about what the real reading are, if dynoed. What you are REALLY looking for is TORQUE. This is what moves your car from still to what mph you want. HP is the top number your motor makes and is used at top end for high speeds. It sound like you have a nice car that will run good and last if you keep control of your right foot. I wouldn't recomend you drag race a T-5 trans. If you roll off the start line this will not abuse the trans. If you 3,000 rpm holeshot the car, trans or clutch with suffer.
As far as the 500-600hp motors heard on the forum, don't believe everything you hear. I have a 482 motor with 610 ft of tork and 560 HP. This goes to 420 rwhp and 480ft of tork. This is fast enough to have the car run low 11.0's if the tires would hook.
True drivetrain loss is about 15-22% depending on rearend, trans, what you are running off the motor, Alt, Waterpump, P/s, drysump oil pumps,and ac compressor. These all drain power.
Until you become a driver, you really don't need 500 hp. There are many a cobra owners here and a few that have died from having too much power and not rescept these cars. Cobras are fast, bural, unforgiving, and react faster than most drivers. Short wheel base also adds to the handling issues. The best orginial drivers say that 500 horse and 600 ft of tork are a safe limit. There are guys running real 700HP at the rear wheels. These are race cars with plates. You will catch the power bug over time, we all do. I went from a 452 to 482 to a 498 nasty motor. It's been a 15 year learning leason and worth the trip is you just remember safety first and know your limits. Driving schools are also a big help. Rick L.

[littlewave]

Wow! thanks for your time Rick. I will read and head. btw. tq about 400 manual steering no a/c. good idea to drive a few summers then see if I need more. thanks again. lw.

[bobcowan]

How much is enough? Don't know, havn't gotten there yet. But I think there's no real answer to that. Some people will say 300, and some 600. Depends on the driver, the rest of the car, and what you intend to do with it.

There's no such thing as too much power, only not enough control.

[WardL]

Don't let your ego take a hit with thinking "only 425 HP". You are looking at a great set up. Yeah, my '66 200 HP Mustang needed more, your Cobra won't need anymore to have the time of your LIFE!

[mdross1]

A lot of cars have what seems like too much power.Mine dynoed at 585hp,at times feel like could use more.Most of the time it is plenty especially around town.Everybodies need for speed is a little different.

[mpanten]

Originally Posted by RICK LAKE

littlewave This is about what the real reading are, if dynoed. What you are REALLY looking for is TORQUE. This is what moves your car from still to what mph you want. HP is the top number your motor makes and is used at top end for high speeds. It sound like you have a nice car that will run good and last if you keep control of your right foot. I wouldn't recomend you drag race a T-5 trans. If you roll off the start line this will not abuse the trans. If you 3,000 rpm holeshot the car, trans or clutch with suffer.
As far as the 500-600hp motors heard on the forum, don't believe everything you hear. I have a 482 motor with 610 ft of tork and 560 HP. This goes to 420 rwhp and 480ft of tork. This is fast enough to have the car run low 11.0's if the tires would hook.
True drivetrain loss is about 15-22% depending on rearend, trans, what you are running off the motor, Alt, Waterpump, P/s, drysump oil pumps,and ac compressor. These all drain power.
Until you become a driver, you really don't need 500 hp. There are many a cobra owners here and a few that have died from having too much power and not rescept these cars. Cobras are fast, bural, unforgiving, and react faster than most drivers. Short wheel base also adds to the handling issues. The best orginial drivers say that 500 horse and 600 ft of tork are a safe limit. There are guys running real 700HP at the rear wheels. These are race cars with plates. You will catch the power bug over time, we all do. I went from a 452 to 482 to a 498 nasty motor. It's been a 15 year learning leason and worth the trip is you just remember safety first and know your limits. Driving schools are also a big help. Rick L.

Rick speaks the truth. That is about the same parasitic loss that I have in my small block. Lots of HP is fun but as time goes by you will get tired of tuning and replacing parts and fixing all the little things that go wrong with a race motor. I also recommend spending the money on a twin disc clutch, that was the best thing i ever did in terms of helping the drivability of my car.

[blykins]

This is the advice that I give everyone that I build an engine for:

Go for as much horsepower as your budget allows, as long as it keeps you in the rpm range that you'll be running the most.

You can get a TON of horsepower out of these engines, but the smaller engines need to start turning some revs to get there. There's no reason to build an engine that peaks at 7000 when you spend most of your time at 2500.

I also tell customers that they will get bored with the horsepower after about a year and they will come back wanting more, so they might as well go big from the get-go.

[littlewave]

blykins I sent an e-mail to ya.

[blykins]

I didn't receive one....did you send it to the address in my signature?

[Voyager]

Is 425 hp enough? You have to decide that based on what is important to you. Talk to the builder about your expectations and your driving habits. Be realistic. Don’t say strip, if all you are going to do is take your wife to dinner in it. Do your homework. It’s a total package, not just engine. Great engine and crappy ______ (clutch/tranny/tires/brakes/etc.) is a recipe for disaster.

I looked for a mixture of outrageous power & sound, coupled with good reliability and decent drivability. When the crate showed up, it was magic. The engine dyno said 515hp/531 torque. Realistically, its way more than I could every use under normal circumstances (i.e. staying out of jail). But turn the key and bring it to life…all to good with the world.

[skippy]

Originally Posted by blykins

I also tell customers that they will get bored with the horsepower after about a year and they will come back wanting more, so they might as well go big from the get-go.

Spot on, I'm one of those guys. Stroked 392 putting 500hp at flywheel before and i slowly grew into its shoes.

Last year i decided to pull the plug (after much research from CC) and am a lot happier. Lets see what my thoughts are in a couple of years (good god maybe a Big Block .. lol .. )


Good luck..

Skippy.

[Hotfingrs]

Let me see, 8 engines in 12 yrs. I guess I get used to the power rather quickly. I must admit though, I hope on I'm my last one, 800 horse and torque is enough.

[Turbonut48]

Or you can use the saying from the infamous CS:

Enough is enough. Too much is just right !!

The Nut