Gearing questions

Since I have the next week off I would like to get the ball rolling on getting this b-body rear under my a-body. When I built my motor last spring I had 3.73 or 3.91 gears in mind for my car. This fall I bought a 489 center section that had a new set of 4.10 richmond gears on it. I know I don't have enough convertor and maybe not enough cam to run 4.10 but what would happen if I said what the hell and ran the 4.10 anyways? Would it make the car boggy on launches? Here is a lil info on my setup:

74 Dart sport
360 bored 30 over, zero decked with about 11:1 comp
Edel Alum heads
Airgap
Comp cam solid 274/280 236/242@50 .502/.511
1.5 rockers
650cfm mighty demon
2500 stall conveter
904

There is also one issue about gearing I still can't comprehend for some crazy reason. I know the higher ratio the more low end balls its going to have but I don't understand why. I know with 4.10 for example that for every 4 revolutions of the drive shaft that the tires turn once. Right now my car has 2.76 gears which I am guessing the DS spins 2.76 turns to 1 turn of the tire. To me it kind of seems like a waste of power if the engine has to turn the Drive shaft more times. Can someone explain this better to me or put it in better perspective?

since you dont have a larger stall converter the 4:10's will help you get out of the hole!!!
you need a 3500-3800 converter and STILL keep the 4:10's..of course it depend how tall your tires are too.

If you ever rode a 3, 5, 10 speed, or whatever bicycle, that will help you understand gear multiplication.

What it boils down to is 4.10 gear would be like trying to get the bike going in first gear. With the 2.76 gears you have now, it might be like trying to get the bike going by starting in 2nd or 3rd gear. You are the engine!

You will see that it will be easier to get it to accellerate faster in first gear (like 4.10). The "engine" revs easier/faster and gets into the higher rpm range faster where it makes more power. A looser torque converter basically does the same thing.


On the other hand, too much gear or converter could be compared to coasting down a hill in first gear on your bike and trying to pedal to make it go faster. It basically causes the "engine" (you) to "rev" (pedal) out of its power range too quickly. You don't accellerate any more!

It's always better to lean on the conservative side.

:scratch: That makes sense, doesn't it? :?:

It may also help to go a little bigger on the accellerator pump squirters and experiment with the cams.

also, gear reduction is a co-conspirator with torque multiplication....
it takes torque to get a car moving...and the more torque to the rear tires, the harder and faster it will accelerate

SO...let's say your engine puts out 300 lb-ft to the driveshaft....

a gear reduction of, say 3:1 will put 900 lb-ft to the axles...4:1 would put 1200 to the axles

the numbers are random, just for illustration, but that's how it works

Thanks for the examples guys I think I get it a little better now. I was thinking of using somewhere around a 26 or 27 inch tire or somehwere in the ball park of 275/50-15. I think maybe I should just go with the 3.73 like I orginally planned. I was just trying to save my self a few dollars for now and with those 4.10 being brand new it seemed like a good idea at first.

if you gonna go with a 26"-27" tire then the 3:71's will be fine but if you gonna go with a TALLER tire then you should use 4:10's.

You can never have too much gear, run the 4.10's and drive it like a rent car