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-   -   Torque & HP for 355 SB Chevy (http://www.hotrodders.com/forum/torque-hp-355-sb-chevy-2334.html)

bigjoedo 04-08-2002 04:44 PM

Torque & HP for 355 SB Chevy
 
I am building a 355CID chevy for street performance. It will be used in a 3900# Monte Carlo with 4:11 rearend & 3000 Stall speed converter.
I have been using "Virtual Engine Dyno" trying to determine the right parts combination.
The current combo produces 195HP and 456 Ft. Lbs of torque @ 2250 RPM. The torque curve hits the max of 482 Ft Lbs @ 3500 RPM. The Hp curve hits the max of 438 HP @ 5500 RPM. The Torque at 5500 RPM is 418 ft. lbs.
My question is: Is this a good combination for street use. Which is more important HP or Torque ? Thanks as always for your help.

Joe

4 Jaw Chuck 04-08-2002 05:09 PM

Torque baby!!! Seriously torque X rpm = HP so depending where you want the torque that will affect the HP. Big HP numbers look nice on a dyno sheet but in the real world torque down low is what will move you. Gearing is a torque multiplier so remember that in your calculations.

reddwarf 04-08-2002 05:27 PM

Actually, [torque x RPM]/5250 = HP

I agree though, torque is most important in everyday driving on the street.

Remember the old saying "You drive torque and sell horsepower"

jimm 04-08-2002 05:53 PM

bigjoedo,howdy! youre using a good virtual dyno. post your parts so we can check them out. if you are not going to be running at the strip then work your engine to produce scads of torque down looow!since you have ve2000 dyno you can swap in different parts to develop max tq. in the rpm range that will be most useful to you,holler back,jimm

bigjoedo 04-09-2002 03:21 PM

Jimm,

I am using a standard Chevy 350 bored 30 over. It is currently rated at 300HP. The parts I am going to add: Comp Cams Hydraulic with 292/292 Duration, .501/.501 Lift, (Lift at 50% TDC 244/244), Roller Rockers with 1:6 ratio. MSD Ignition, Edelbrock Performer RPM Intake. Holley 750cfm carb. World Products Sportsman II heads, with 200cc runner volume, 64cc chamber, 2.02 Intake, 1.60 Exhaust valves. Headers

Joe

jimm 04-09-2002 05:50 PM

,what vehicle?rear end gear ratio,hey bigjoedo!,ok, for starters you know that h.p. dyno programs are limited in their ability to determine output.so, with that said we can keep a proper perspective.what pistons are you running?,comp. ratio?,what size headers?,get back to me, jimm

critter 04-14-2002 11:34 PM

rule of thumb (the way I learned it)
torque gets you movin
HP keeps you movin
sounds to me that your on the right track would like to know how things turn out

F-1Rodder 04-17-2002 10:11 AM

Considering the weight of your car, you need to focus on overcoming gravity. So focus on toraue production and consider making it a 383. The cam you have selected will require a high stall converter which will generally wake up your car a lot. Go with at least a 3000 rpm stall. That cam is pretty big for daily driving and you will see your mileage go down the toilet with that cam.

Everybody is looking for performance and the stark reality is that the more power you produce at higher rpms, the less driveable it is at lower rpms. Seriously, you can end up with a car which is a total dog going to the grocery store. So define carefully what your objective really are and keep asking questions until you get there.

I remember building a sport car which had an aggressive cam and big carbs. It would scream from 5000 rpm to 8000 but at 3000 I would put the accelrator down and nothing would happen. Any 18 wheeler would out accelerate me on the freeway at legal speeds.


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