Hey, I wanted to figure the horsepower of my truck without dyno'n it. Found this equation and was wondering if it works. Horsepower= weight divided by estimated time by 5.825 times third power. When I did it, it came out to 211. The only thing I have added to my 351 is a K&N filter kit. So I was wondering how close this is since Im not sure of stock horsepower.

 

What year is your motor? How many miles are on it? 211 is a pretty reasonable for at the flywheel power but 211 at the rear wheels on a stock non-lightning 351 is pretty optimistic. What is the formula trying to calculate. Those formulas kind of suck. Does it figure on gross or net? One formula I used said that I had 175HP from my 18.4 sec e.t. My 360 came stock with 174. I don't think it has the power it did when new. What was your e.t out of curiosity?

 

When I dynoed my truck with only the K&N air filter, it got 171 HP and 267 ftlbs of tq. What year engine do you have? I'm thinking 211HP is fairly high.

Daywalker
92' F-250HD 351 4x4 xlt 4.10 ZF 5speed supercab longbed

 

It also says that with 418 HP my 390 will take me from home to the grocery store in 12.5 seconds. I don't think so. Even with perfect traction ,which won't happen, my truck won't get the job done that quick.

 

My truck is a 1995 F250 4X4 with a 351. My time was 18 sec in the quarter. I have 3.54's and it came with 4.10's. So, the rev limiter has changed. The weight I used for the formula was 6300 pounds.

 

Your truck weighs in at 6300 pounds? Sounds more like a GVW rating then the curb weight for model.

 

Mine weighed in at 5700Lbs.

Daywalker
92' F-250HD 351 4x4 xlt 4.10 ZF 5speed supercab longbed

 

GVW is actually 8800. 6300 is what it weighed when I had to go get it tagged here in California. She has a tool box in the back with a couple hundred pounds of tools and she has a eight foot bed on her also. Actually, I thought 6300 was a little high. Hey, how much do u all pay for tags each year? I have to pay mine at the end of this month and I have to pay........$276.00. What a rip off!

 

I saved about $80~100 a year by having a shell on mine when I got it inspected. This allows you to get a non-commercial plate and doesn't require weight check.

The down side is that if you have a load in the back that wouldn't fit in a regular car, you can get a ticket.

 

i think 6300 is a little high, mine weighed in at 4500 unlaiden when it was stock, now its prolly a little lighters since i ditched the heavy exhaust manifolds and stock exhaust and shell...but what i really wanted to know is, where did u guys go to put ur truck on the dyno to see how much HP/TQ it has? mine suppossedly had like 235HP and 415# torque stock, but i want to really knwo what i have now since i have been ungrading it....thanks, oh and by the way,i live in huntington beach, ca amd i pay 120 a year for registration....why is urs higher than mine???

1977 F250 460 C6
MSD, K&N, hedman headers,
dual flowmaster 40 series,
holley 750, B&M transpack

 

6300 sounds a little high to me too. I have a '96 crew cab 4x4 F350. It's weighed in at 6500 empty on three different scales. That's including a 460, D60 front axle, and 35s on steel wheels.