On the street,
it's all about the combo
which IMO, starts with torque to the tire contact patchs. No matter how you slice it, no matter what you call it, or how you measure it ; TORQUE to the road is what moves you out, and the more you got, the quicker it's gonna move out; That is the whole point of gears, transmissions, and Torque-convertors. Those are called TORQUE multipliers for a reason.
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Ok just for the heck of it; say you had that 455hp engine. And say it made 340 ftlbs at 2600 (168hp for those that want to know), with that tiny 3.375 arm.
At Zero mph, by the time it gets to the road ; it might have been multiplied out like this;
340x1.8(in the TC) x2.45 (in the trans) x3.55(in the rear)=5322 WOT ftlbs to the patches. NOBODY ever calls this 5322x2600/5250=2636hp
Now suppose your 383 made only 390hp at 4500, but it made 355ftlbs at 2600, and say you put 3.91s in the back. This now comes to
355x 1.8 x2.45 x3.91=6120 ftlbs@WOT
>Which combo is better? Too soon to answer, is the correct answer.
Lets look at 32mph in first gear;
With the 3.55s this is ~3630 rpm@WOT. How much torque is that 455 gonna make here? I'll guess at least 420, and I'll guess the TC is down to 1.2 ratio,so
420x1.2 x2.45 x3.55=4384 WOT ftlbs.
How about the 390?
With 3.91s, 32 will be ~4000@WOT. How much torque is this gonna be? IDK lets guess 380, and the TC also at 1.2, and so
380x 1.2 x2.45 x3.91=4368 WOT ftlbs.
>Which combo is better? Too soon to answer, is the correct answer.
What about at the 1-2 shift? This is the big deal.
With 3.55s the 455 engine will drop from 5900 to 3400, and I guess 410 ftlbs, so
410x1.1x1.45x3.55=2320 WOT ftlbs, compared to
with 3.91s the 390hp engine will fall to 2950, and I guess 375ftlbs, and
375x1.1x1.45x3.91=2340@WOT
>Which combo is better? Too soon to answer, is the correct answer.
What about crossing the finish-line at 60mph, in second gear?
the 455er is gonna be at ~4030rpm and guessing 450ftlbs, and the TC at 1.1, so
450x1.1x1.45x3.55=2548 WOT ftlbs
the 390hp engine will be at 4440, peak power so 390x5250/4440=460 ftlbs, and the TC still at 1.1,so
460x1.1x1.45x3.91=2869 WOT ftlbs; wudjalookitdat!
>Which combo is better? Too soon to answer, is the correct answer.
Here is the great Street-Machine leveler
65mph with 3.55s is 2870 at zero slip, and is 3160 with 3.91s, a difference of 290rpm
>Which combo is better?
Now keep in mind, I have no torque curves to work from; and all I got is best guesses and I freely admit it. But the point is not in the numbers exactly, but in what the gears can do for your streeter. And you don't need to be a brain surgeon to see that if you had just one more gear, an overdrive, it would open up a whole new world for both of these combos...........
But it could also introduces another possibility; a less powerful same-sized engine, now running say 4.30s,lol.
Because a streeter is gear-handicapped so badly in the zero to 60 contest, it almost doesn't matter how much power over 300/350 she has; the tires and the car are gonna be the limiting factors, depending on with what exact engine and combo you use to get there.
Here's the thing; at zero mph you don't need 5322 or 6120 ftlbs; those numbers are about double what you need to break loose the biggest street tires you can fit into your wheelwells.
Nor do you need 4300/4400 at 32 mph; At WOT, your tires are still smoking.
At the 1-2 shift, the 390 is keeping right with the 455.
But what is going on at 60 mph! The 390 has jumped ahead!
>So.................. Which combo is better?
Only you can answer that.
With the right gearing, from zero to 60, even a 318 can be a blast.It doesn't run outta steam until it has to start pushing wind. I ran a smogger teen with a 4bbl and headers..... and 4.30s, and it was a hoot!
