Hot Rods Horsepower minimum, got a number?

There are a whole bunch of ways to make big HP, and not all of them are real expensive. Just gotta get creative.

 

The only limiting factor?

"Speed costs money, how fast ya wanna spend?"

 

These days, V8 with the typical aftermarket intake, carb, cam, headers, ignition, etc., and a 4 speed works for me.
Horsepower?, not a concern...I'm an old man, and drive like one.

 

Don't worry mate! I've dusted a few 500hp Falcon GT's track cars with my 145hp Lotus Cortina.
But the Cortina only weighed in at 720 kg [1584 lbs]
Which is 10.92lbs/hp
But a 200lb driver adds 12.7% to the weight [Which is 12.3lbs/hp]

People always refer to "power to weight", but they don't factor braking power to weight, and cornering power to weight.
The common denominator here is "weight"


Horsepower numbers are purely "wank factor" needed to prop up fragile egos.
A 600 hp ZO6 Corvette might sell, but these cars seldom use/need more than 300-350hp on the street.

For a 3000 lb street car , I personally think 250hp [at the flywheel] is more than satisfying.
This is enough to achieve a 13.6 to 14.0 quarter mile.
Any more than this for a novice is like giving a toddler a loaded 44 magnum.

Whenever you double the speed, you need 4x power! so coming off the corners at 80 mph in a 2600lb car with 600hp [my old Corvette] would be under powered.
But a Novice/Dickhead standing on the gas at 15 mph with 250-300hp Mustang leaving a cars'n'coffee, and you'll see the phenomenon of cars attacking bystanders.

Whenever you double the speed, you need 4x power it is easier to get gains in the first 1/8 mile than the last 1/8 mile on the quarter.
Mechanical "leverage" is the secret.

 

My cars 3660 lbs. with me in it so needs more poop under the hood.

 

Before you start thinking 500 HP better start thinking about if it's usable in the vehicle and how your using it.

Know a guy who has 500 HP in a roadster . You can't have a discussion about his car with out hearing its got 500 HP a dozen times.
I have never seen him drive it fast or hard. He might light the tires up leaving somewhere but I never see him go straight if he does and would likely crash if he ever hooked it up stayed in it.
I honestly bet if he had 375 HP he would notice a difference.

I'm putting about 475 Hp SBC in my 57 Vette that's a old drag car put back on the street .
Other than going in a straight line the car doesn't have the brakes, suspension, tires or even seats to really use.
Sure it will be fun to wack the throttle and such but with out some upgrades I can't remotely run the car hard.

Guys saying 400 is not enough need to take a ride in a prepped newer Camaro ,Mustang Corvette or the like on a road course with a long straight and turns with a honest 400HP.

More fun driving a slow car fast than a fast car slow.

I have a fiberglass 27 T project ( Old Speed way body and frame)
I have gone back and forth on what to power it with from a 150 HP 4cyl to 800 HP Nitrous add BBC .
This week it's a 327 I built in 82 that put a 67 SS Chevelle in the high 12's with 5-13 gears and 30" slicks
It might be 400 HP likely less.
I seriously doubt I could drive that 27 remotely hard with 8" wide rear tires , 6" fronts, drum brakes , corvair steering .
Sure it's likely a 11 second car if I put slicks on it but on the street 95% will be doing under 70 MPH most under 55 MPH .
That engine was hot shit in the 80's
It's still going to haul ass in a 2000 pound car in 2024 and will likely be detuned for pump gas.

My 96 Mustang GT only has about 250 HP and it scares the crap out of people if you really use it all with the suspension, brake and tire up grades in the twisties were you can drive hard out of a turn.
A new Mustang has triple and guys want more.
Most don't or can't remotely use what they have .

5000 pound truck then sure give me 500 HP

 

Well said .

Some of the new stuff is like a sport bike on the street. Half the power never gets used .
I'd be more impressed of a driver that can truly drive a new Vette on a track to its full potential than the car its self .

 

I used to be in the hp/lb group and 10:1 is a healthy number, 14:1 not so much but it will haul the groceries.
These days I am all about grunt and perfectly happy with the 1000lb-ft in my OT daily driver truck which is about 1 lb-ft/9 lbs at the curb. Yes, I leave the traction control on.

 

Imma bout to stuff a whopping 160ish hp in our flatbed

can’t wait.

no traction control needed

 

Why so conservative?
Those little "A" series engines easily turn 10k+
Horsepower is the "size of the bang" multiplied by the number of "bangs per minute" [quoted by Keith Duckworth]
One thing that is a "must" on these small bore engines [including my Cortina] is a close ratio gear set to keep the engine "on song"

The secret to these drivers is "Tyre management". You need to develop a feel for the tyre adhesion limits
Most road racers can out perform ABS braking because of this. [it takes a bit of practice]

One of the most difficult skills to learn is squeezing the brake pedal, the next difficult skill to learn is lifting off the brake pedal [when trail braking]
Racers use the brakes to transfer weight for corner entry, not slow down! They don't want to go slower

If I had a choice of only 1 modification to a vehicle for racing ........ It would be Tires

 

My 64 chevy truck in high skoo had advertised 220 hp, 283, carter 4barrel, stock factory motor


.

 

That's the joy of way too much power...no need for all that laborious downshifting!

 

But shifting is fun

 

So is mashing the pedal and suddenly going real fast

 

Every time I get in my 36 pickup, I realize what a death trap it is with its 350, so whatever it puts out is fine by me.

Frankly, I had fun driving my old 2.3 l five speed Ranger and the old 240D Mercedes.

To me, it’s more of a what can you Erin out of whatever you are driving at the moment than what the absolute power is.

Plus, my wife is uncomfortable with participation in unrestrained speed demonstrations on land or on the water.

 

Or upshifting??

Even my old Corvette [600hp and 659 ft/lbs] needed to downshift from a 172mph straight into a 40mph 1st gear hairpin corner.
Heal Toe downshifting went out of vogue for a while [mid 80's to mid 90's] when drivers would simply apply the brakes and turn in.
When the car "takes it set" they would simply select the exit gear [4th to 2nd etc]requiring only 1 shift.
Rowing down the gears came back into vogue with sequential transmissions.

 

I will say, I think you muscle car guys are missing out: banging around in an ol' jalopy, gas pedal flat to the floor, engine howling, tires squalling as the body roll about dislodges you from the vehicle is a real hoot. You can just drive around nearly everywhere full throttle.

My minimum HP for driving a classic is proportional to how cool the car is. By some quick math, a pontiac Aztec would need about 900hp to be driveable.
Fortunately, most classics are interesting enough that the required HP is pretty low.
For a sub 2200-3200lb car, manual transmission, 80hp is about minimum for keeping up with traffic without too much stress, 125-200 is desirable.
For something like my Plymouth, around 3100lb, the 95hp gets me around OK, but it is sometimes stressful, when traffic is heavy and I am trying to merge, or make a dicy maneuver. It does it, but you really got to think and plan.
I am looking forward to having an OD trans and my dual carbs installed. And extra 30hp would go a long way.

 

As long as I can step down, smoke tire for a long ways, and feel the pushback in the seat, i'm good. I have cars for different things........ Street cruiser? say 400hp with a lil gear and converter...... All out is another story......

 

You beat me to it. A/F ratio not even close.

 

Just asking , your 427 should of pretty easily, made more torque & Hp then shown,
Afr nowhere near correct ... those headers should've been glowing Cherry Red..
Is this 8:1 - 9:25 compression
& with a small head cfm, 170-180ish.
Cam ?
Carb size ?
427 sbc like to breathe ,
Heads 200-220 (23deg) mild
Compression 10:5 -11:5 pump gas,
Cam starting .560 up, duration depends on where you want power making ,
Carb cfm 800 plus

Denny , I would not trust that print out,
You might Be disappointed under false information!!!!
@ the beginning of the pull being
SSSooooo Lean ,,, I would think popping

 

I doubt the 02 sensor was taking a reading in the right place. If it were that engine would be detonating itself to death.

 

What’s an O2 sensor?

 

200 for every day driving. 375 is for having fun. 750 is for a great afternoon at the track

 

40 HP. I might build a "banger" some day.

 

Its sensor that measures oh2

 

Where could you put an O2 sensor that would allow readings that far off? For max power I think you want 12.5 - 13.5 AFR. Running super lean is a good way to burn a hole a piston or 8.
I guess the HP needed is whatever trips your trigger and you can afford.

 

My car came with 202 claimed hp in 1956 @ 4600 rpm. With better flowing later exhaust manifolds and 2 four barrel carburetors I would hope it has 225. I have seen 4500 in second gear of the automatic transmission a few times and a true 105 mph in high gear when I “blow it out”.
I have no reason to want more as that’s more than I could hope for on a vehicle manufactured 67 years ago with an original type engine.
No one I know drives their vintage, classic, hot rod, etc within 3000 rpm of it’s highest hp more than 1/10th of 1% of the time they drive because you can’t safely on the roads today with the drivers you must dodge.
Horse Power is over rated…

 

The bottom end was basically stock Austin America 1300, and stock, pistons included. And man, those are heavy! I did have ARP bolts holding it together at least...

The new one should be better. Aluminum head, high lift roller rockers, much better pistons, rods rebuilt properly, Weber 45DCOE on 6 inch manifold, LCB header, cam tbd. But that's another story for another time...

 

Crap.
I’ll remove 4v intakes and use a 2v.
And swap out headers for manifolds.

 

Minimum horsepower needed? Everyone's answer will vary to suit themselves.
Maximum required is an easier question to answer.
What can you honestly get to the ground with your vehicle's mass/weight distribution/gearing/suspension/tires?
Any more than that is spending money for nothing........