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Estimated Horsepower (Just Curious)

RJRENTON said:
Was that "SIMONIZE paste wax"....in a flat can which required the "wax on- wax off" technique or something like "BLUE CORAL" or maybe even "TURTLE WAX".......
BOB RENTON
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Simonize flat can and sponge applicator
 
Back in the day I had a 383 4spd road runner. Bought it new; only car I had. By 1970 I had a dp4b with a 780vs holley, 280/.480 lift hydraulic cam, hooker 1 3/4" headers. 4.10 gears. Car was very consistent 13:20's@106mph. Traction was always a problem. Anyhow, I estimate net horsepower about 370.
 
lewtot184 said:
Back in the day I had a 383 4spd road runner. Bought it new; only car I had. By 1970 I had a dp4b with a 780vs holley, 280/.480 lift hydraulic cam, hooker 1 3/4" headers. 4.10 gears. Car was very consistent 13:20's@106mph. Traction was always a problem. Anyhow, I estimate net horsepower about 370.
Click to expand...
so what do you think your 383s gross hp number at the flywheel was?
 
DanielSlocum said:
so what do you think your 383s gross hp number at the flywheel was?
Click to expand...
Probably 370. The 370 number was open exhaust. I think 350 thru mufflers. I question how real all these TV/internet/magazine numbers really are. Even if you get a big cute number on an engine dyno you still have to put the thing in a car and run it, and that's water pumps, alternator, maybe power steering, belts, etc. Gross numbers just aren't real. Anyhow that's how I look at it.
 
If you just want a number to impress strangers at a car show, imo you're doing it wrong. Just make up a number, but be reasonable about it. Don't make an obviously outrageous claim.
I go the other way. Somebody asks about my 500hp 406 chevy, it's a 370hp 350. My 522 is gonna have 413 stickers on the valve covers. When they ask about my rat motor, it's a 100 over 375hp 396. Not my fault if they don't think 100 cu in over.
 
I tried it, a pretty good number. Wallace has similar calculators for 1/8 mile as well.
Wallace uses a fixed 10% for wheel horsepower from derived crank horsepower. I think that is very optimistic. I usually use 20% for an auto trans car with a hi stall converter.
 
Just imagine having 400 horses pulling your car down the street. That makes it more fun already!! Bench racin'. Sounds like a bunch of horse**** to me!! haha.
 
4speed68rt said:
Just imagine having 400 horses pulling your car down the street. That makes it more fun already!! Bench racin'. Sounds like a bunch of horse**** to me!! haha.
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To use your "400 hp" number, horse power is usually stated at *** rpm....where did the number come from??....likely, the owners imagination. To develop the 400 hp, the car would be traveling at, say 90+ mph.....or .....perhaps just in neutral revved to *** rpm for 20-30 seconds......which proves nothing.....show us your dyno curves corrected for temperature, air density and operating conditions.....sort of like the apples vs oranges comparisons.........???
BOB RENTON
 
RJRENTON said:
To use your "400 hp" number, horse power is usually stated at *** rpm....where did the number come from??....likely, the owners imagination. To develop the 400 hp, the car would be traveling at, say 90+ mph.....or .....perhaps just in neutral revved to *** rpm for 20-30 seconds......which proves nothing.....show us your dyno curves corrected for temperature, air density and operating conditions.....sort of like the apples vs oranges comparisons.........???
BOB RENTON
Click to expand...
I agree with the dyno numbers.
Hp is a calculated number from torque @ rpm. Watch dyno pulls. Torque and hp # is the same at 5250 rpm.
I’ve seen 450 2L turbo engines be slower than a 320hp 360cu in in a a body. The cars were very close in weight. Cause his power band was so small and I had reasonable torque from 3000 rpm till 5500 rpm.
Mathematically, horsepower equals torque multiplied by rpm. H = T x rpm/5252, where H is horsepower, T is pound-feet, rpm is how fast the engine is spinning, and 5252 is a constant that makes the units jibe. So, to make more power an engine needs to generate more torque, operate at higher rpm, or both.

My 68 charger’s 440 made 485hp on the engine dyno…. Doesn’t sound like it’s much or fast.
At 2500 rpm is made 500ft lbs. torque
3800rpm 550ft lbs
At 4800 rpm is where max hp 485 occurred 530ft lbs torque
And 458 ft lbs torque at 5500… carrying
the hp at 480 hp
So doesn’t sound like much other then it maxes massive torque everywhere. The car is reasonably fast and anything under 40mph with 3.23 gears it will haze the 28x12 rear tires.
It’s not a race car but it pulls hard. I’m at 2800 rpm at around 65mph. No down shift required it will accelerate.
It still pulls hard at 6000 rpm but it’s a 440. Don’t need to rev it it just pulls.

So don’t worry about what the hp rating is. I tell people when they ask what kind of power my car makes 400+. How does your car feel and does it put a smile on your face when you drive it. I could make more hp with a bigger cam but all the does is move the torque curve up. Again higher torque at higher rpm = more hp. I like my torque where it is cause that is where I run the car 95% of the time.
Drivability for what you want and a smile when you push the go go pedal is what is important in my opinion.
 
Tman100 said:
I agree with the dyno numbers.
Hp is a calculated number from torque @ rpm. Watch dyno pulls. Torque and hp # is the same at 5250 rpm.
I’ve seen 450 2L turbo engines be slower than a 320hp 360cu in in a a body. The cars were very close in weight. Cause his power band was so small and I had reasonable torque from 3000 rpm till 5500 rpm.
Mathematically, horsepower equals torque multiplied by rpm. H = T x rpm/5252, where H is horsepower, T is pound-feet, rpm is how fast the engine is spinning, and 5252 is a constant that makes the units jibe. So, to make more power an engine needs to generate more torque, operate at higher rpm, or both.

My 68 charger’s 440 made 485hp on the engine dyno…. Doesn’t sound like it’s much or fast.
At 2500 rpm is made 500ft lbs. torque
3800rpm 550ft lbs
At 4800 rpm is where max hp 485 occurred 530ft lbs torque
And 458 ft lbs torque at 5500… carrying
the hp at 480 hp
So doesn’t sound like much other then it maxes massive torque everywhere. The car is reasonably fast and anything under 40mph with 3.23 gears it will haze the 28x12 rear tires.
It’s not a race car but it pulls hard. I’m at 2800 rpm at around 65mph. No down shift required it will accelerate.
It still pulls hard at 6000 rpm but it’s a 440. Don’t need to rev it it just pulls.

So don’t worry about what the hp rating is. I tell people when they ask what kind of power my car makes 400+. How does your car feel and does it put a smile on your face when you drive it. I could make more hp with a bigger cam but all the does is move the torque curve up. Again higher torque at higher rpm = more hp. I like my torque where it is cause that is where I run the car 95% of the time.
Drivability for what you want and a smile when you push the go go pedal is what is important in my opinion.
Click to expand...
Thanks for the response. After reading through this and another member post about stumbling in 1st gear, I went back to my timing and set initial at 30* based on the fact that it has very low vacuum.

Got some non-ethanol 91 octane and added 2oz per 10 gallon octane boost.

The car now roasts the tires from a stop, 10-15 roll and when I shift into second it roasts em again. Pulls very hard at 50mph when I goose it without a downshift.

I do get a very slight valve chatter at higher speed so it still needs to be massaged a bit.

But I am absolutely thrilled with the performance regardless of the actual Horsepower.
 
Justasgood said:
Thanks for the response. After reading through this and another member post about stumbling in 1st gear, I went back to my timing and set initial at 30* based on the fact that it has very low vacuum.

Got some non-ethanol 91 octane and added 2oz per 10 gallon octane boost.

The car now roasts the tires from a stop, 10-15 roll and when I shift into second it roasts em again. Pulls very hard at 50mph when I goose it without a downshift.

I do get a very slight valve chatter at higher speed so it still needs to be massaged a bit.

But I am absolutely thrilled with the performance regardless of the actual Horsepower.
Click to expand...
Congratulations! You've hit the magical 450hp mark! :lol:
 
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