So my 1999 auto 24v came with  215 hp 420 ft lbs torque After 275 rv injectors and old style edge on high add 100 hp so 315 hp what’s my torque ft lbs now ?  And how are these numbers figured out.  

i would like to understand 

Why is a new ho Cummins 420 hp and 1000 ft lbs of torque  then.  I’m trying to understand

Well there is much more to it. You can change the torque number just by changing tires. So final ratio will impact the final HP/TQ. Then there is rotational mass less rotational mass the quicker to accelerate and more torque is passed to the tires. For every one pound of rotational mass you remove that is like taking 8 pounds off the frame. This is why true racing rear slicks are super light. Then I can dive into engine functions like timing. Currently I've got a tune capable of 28 MPG. My empty EGTs are like 500 to 550F at 65 MPH. So less drag and proper gearing setup you can get efficiency up which means you not wasting energy in heat. Excess heat is wasted power. This includes axles, transmission, engine, etc.

So mike. Say you get 28mpg 375hp what is your tourge guestimate. To keep things simple lets elimate things exstending passed the rear crank seal.

I know I'm past 375 hp. I'm guessing between 450 to 500 hp and about 1200 foot pounds. Turn up the Quadzilla up it's quite easy to light the tires up. 

Edited October 13, 20213 yr by Mopar1973Man

So tourge is 2.4xhp

So 315 hp makes about 750 ft .lbs torque. Sound about right

Maybe a little high I think 

I would say 1.4 -1.5 is a close factor not 2.4 so 215 /420  would be 325

Sorry.  315 hp would be about 600 ft lbs torque

@Turbo Terry you are close 
 

Torque = HP X 5252 divided by RPM

 

you can switch it around 

 

HP = Torque X 5252 divided by RPM   

Again like I said...

23 hours ago, Mopar1973Man said:

I'm guessing between 450 to 500 hp and about 1200 foot pounds.

 

I've not been on the rollers in a long time last time was back in 2006. I rolled 381/831 with just a Edge Comp, stock injectors.