Hello, lets say both motors have 425 hp, auto trans 2200 stall w/ 355 gears. The first motor is a 355 and the second motor is a 383. Everything being equal except for the stroker crank, who would win in the 1/4 mile?:flag

 

Off the top of my head without thinking too much about it, the 383ci would win because he's going to have more torque and wider flatter torque curve meaning he will have more power thru most of the RPM range

Now if they both had the same torque it would be closer but I would still give the edge to the 383 because of the torque curve, the 355's torque curve wouldn't be as flat even though the peak torque was the same. You are looking for power through the RPM range in each gear

 

It,s all about TRACTION....The first 60 feet is crucial the 383 will likely spin with that extra torque.however if they both had perfect setups then the 383 would certainly out run the 355!!!

 

383. More TQ or lower rpm HP.

 

IF all the other things are 'equal', [theoretically] the larger engine would always win. But, how each car is driven/launches makes all the difference in who wins and who loses a drag race. If you race those two cars systematically...by running many times and switching drivers for an equal number of races...the 383 might lose a few close races, but it would be very few.

 

I think the OP meant, all things being equal except for the motor cubic inches. Wayne is probably right to say the 383 has the torque advantage. It's no more expensive to build a 383 than it is a 350. The 350 would have to have a more radical cam to make up for the lost CI to attain 425hp making it more of a pain as a daily driver. Remember, extra CI's is really free HP. My money is on the 383 to hook up and get better 60' times because of the torque. Thats assuming both cars have sticky tires.

 

Would a 355 with 425hp be fun to drive on the street? I believe that's more hp than any 350 ever put in a Vette.

 

Anyone driving a 355ci with 400 range hp. How is it to drive on the street? Is it fast, fun to drive.

 

i have in the range of 400hp in my 355. th350 trans and 3.08 gears. gears are a little weak and it would benefit from a looser torque converter but it's pretty stout. you can make north of 500 bhp in a 355 with the right cam and heads. which are next for my motor.

 

hmmmm.
my 2 cents worth....
But lets keep to the original posters question regarding drag race performance....
Performance in a drag race has nothing to do with street manners.


A 355 putting out 425 hp will need good heads and bigger cam and will require more rpm to achieve the goal... lets say 6500 rpm for peak power.
425hp in a 383 is easily achived with around 5000~5500 rpm.

That being said, whilst the torque of a 383 might be higher at lower rpm, you will need to change to next gear to sustain good accelleration.
A smaller capacity motor which revs higher, will outperform the bigger motor, as the advantage of gearing will provide a better average torque over the entire 1/4 mile.

Seen it happen all too often.
Seen plenty of 425hp big blocks that get whooped by 425hp small block mice

Same scenario with a 383 vs 355.
Whichever motor offers the highest torque in the higher rpm range will have an advantage due to gearing.

Yes, performance is all about producing torque.... but the higher the rpm at which it is produced, the quicker you will be.

Ever wondered why Formula 1 engines spin to 19000 rpm?

 

The OP said both engines produce 425hp. Assuming the 383 produces peak torque at a lower rpm, it must produce more torque overall since hp = torque X rpm X conversion factor. Since both cars start at 0 mph, the 383 reaches peak torque sooner, therefore is accelerating quicker than the 355. All this advantage would occur in 1st gear. Even if they ran the same through the upper gears, the 355 would never make up the ground lost in 1st gear.

 

The OP says they both make 425HP and nothing about making the same torque. So with just this torque advantage to the 383ci stroker it would smoke the 355ci in the 1/4 mile.

If somehow the 383 had some mismatched parts and made the same the torque as the 355ci then it would be up in the air as to which one would win, I would still bet on the 383ci though because the torque curve would be flatter than a "peaky" torque curve the 355ci would put out therefore more overall power under the curve

 

If both engines make 425hp and the 383 does not rev as high, then the 383 MUST make MORE torque. Like I said, HP equals torque times rpm times a conversion factor. The 383 would win.

 

firstly, we were not given any constraints on rpm. (edited)

All I am saying, is if you want to get best performance for racing, you need to consider the advantages of gearing.
And that is why a higher revving motor will give the benefits, of sustaining the torque multiplication of remaining in a lower gear longer due to extended rpm, and/or combined with the advantage of running a diff ratio like 4.11's vs 3.55's.

I won't argue that a 383 will be a better street motor.

But I will say it is not necessarily going to be quicker than a properly setup car with a performance 355 over the quarter mile.

Each of these motors really requires different setups regarding gearing and torque converters to maximise performance at the strip.
Tyres play an important role obviously... Having a lot more low down torque and smoking up at the launch is NOT the quick way down the track.

If both are setup ideally, the difference will always come back on the driver's ability.

 

For what its worth and to propogate the discussion with some numbers.....

using a dyno simulator I generated some dyno results of 2 motors...

Here's the dyno results of a healthy torque monster 383 with 425 hp at 5000 rpm - a bit too optimistic, but good for this argument.

rpm hp lb-ft
2000 168 442
2500 230 484
3000 274 480
3500 319 479
4000 365 479
4500 403 470
5000 425 446
5500 424 405
6000 385 337


and here's the dyno of a 355 with 425 hp at 6000 rpm

rpm hp lb-ft
2000 136 358
2500 174 365
3000 210 367
3500 270 406
4000 323 424
4500 369 430
5000 404 424
5500 421 402
6000 425 372
6500 412 333
7000 395 296

Wow... look at all that torque difference down low... over 120 lb-ft tq. advantage to the 383!

But here's the rub.
Placing this data into a drag sim, and limiting rpm on the 383 to 5500
but allowing the 355 to rev to 6500, the results with both cars running 3.55 diff gears with a TH400 box were closer than you'd think.

In fact, with hi-performance street tyres (what ever they might be)
the 383 resulted in a 12.635 @ 114.3 mph (with lots of traction issues)
the 355 resulted in a 12.515 @ 114.2 mph

Putting on some mild race tyres made a significant difference, allowing the 383 to hook up and result in a 11.553 @ 115.4
and the 355 lost out with similar tyres with a 11.741 @ 114.6

Now if your serious about drag racing with a peaky engine that pulls 7000 rpm, you'd opt for 4.11's in the rear with a 3500 to 4000 rpm stally!

This is where the higher revving smaller cubed 355 posts an 11.496 @ 115.3 mph

Like I said, setup of the overall car will define actual performance.

Which would I prefer...
well, actually, a 383. But 425 horses isn't enough