Help me pick a gear ratio....

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if you are going to install a GV overdrive I would go to 3.55:1 or 3.76:1 ratio

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3.55 or 3.73

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F-berri ..... THINK about it this-way. As many miles as you put on your car ... how many of those miles benefit from that stiff gear ?

MILES ? ... how about measuring it in FEET !!

I have a car that is lighter than yours ...a 62 Belevedere with lotsA' fiberglass ...and have a 2.76 gear in it and I LOVE IT.

SURE the car doesn't gate that hard(1.82 vs 1.65) .... but with a shorter gear ... those "100-roll" shots are fun .....

And you will love that MPG.

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Eventually I intend to install a Gear Vendors unit.

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Hey, Doc, I know you keep bragging about your 12 sec car that gets great MPGs with 2.76 gears. have you ever considered that half the argument is in all the glass parts on the car? your car weighs significantly LESS than the average A-body.

I think weight has more to do with MPGs than engine size or gear ratio. I'll go back to the Dakota's to illustrate this-- a 3.9L dakota gets 16-18 MPGs. a 5.9L dakota gets 15-17 MPGs. why do 2 engines, WAY different in size, get similar MPGs? what's the same? vehicle weight and aero. the hp needed to move 4,000 lbs through the air is the same regardless of the engine size, and to generate that Hp, you have to burn X lbs of fuel/hr. doesn't matter if you're burning it in 6 cylinders or 8...it's the same total amount.

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Hay Tom .... then lighter weight sure helps in the ET dept ... but not-much-at-all for fuel econ. ... and the AERO of a 62

PLUS the motor is a bit down on power.

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TALLER GEAR....numerically lower gears are TALLER/HIGHER, numerically higher gears are SHORTER/LOWER

by your logic, "low gear" in your tranny would be 3rd (1:1) not 1st (2.45:1 for a 727)

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Hey patrick ...I am talking about REAR END gears. Now if you can't accept that ...... BITE ME !

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Another consideration is the 3000 rpm stall speed of the converter. I know that this car can never be a fuel sipper, but I wonder if I need to target a freeway rpm somewhere near the stall speed to avoid cooking the trans? The 3.23 set spins the motor (Or the other way around) at about 2600 at 65. Maybe the "final drive" with the GV should be near 3.23. With this in mind, the GV has an OD ratio od .78. The 4.10 X .78 is 3.20 while the 3.91 X .78 is 3.05.
What are your thoughts on cruising UNDER the converter stall speed? It seems that the motor might act a little lazy and inefficient.

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Eventually I intend to install a Gear Vendors unit.

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3.55. then with a gv it should b around a 2.76. best of both worlds.

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3.55's, I'm quite happy with them in my car, I went from a 2.76 open to 3.55 suregrip. Although I don't have the size car nor the power you have. Instead of a cam swap why not throw a suregrip in there instead, just a thought.

You might try one of the online calculators and play with the numbers a little, write down the different combo's that you try as you go.


http://www.ramblerman.com/blazer/gearcalc.htm

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Another consideration is the 3000 rpm stall speed of the converter. I know that this car can never be a fuel sipper, but I wonder if I need to target a freeway rpm somewhere near the stall speed to avoid cooking the trans? The 3.23 set spins the motor (Or the other way around) at about 2600 at 65. Maybe the "final drive" with the GV should be near 3.23. With this in mind, the GV has an OD ratio od .78. The 4.10 X .78 is 3.20 while the 3.91 X .78 is 3.05.
What are your thoughts on cruising UNDER the converter stall speed? It seems that the motor might act a little lazy and inefficient.

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my understanding is that a GOOD converter, it won't matter. it'll only slip when you're giving it lots of torque. so part throttle cruise down the highway and it won't slip much.

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a good high stall converter won't slip significantly more below the stall speed than above. stall speed is the RPM of max torque multiplication. a "tight" high stall converter with tall gears is a good compromise, especially if you have a torquey motor.

I had 3.55's with 27" tall tires and HATED it, buzzing along at ~3300 RPM at 75moh on the freeway got old after about 20 minutes. I put an A500 in and kept the 3.55's. if I didn't have the option of an OD tranny, I wouldn't go more than 3.23's, possibly even 2.94's, depending on tire size.

and Doc Fiberglass, yes I was talking about rear gears, too.

TALLER (higher) gears are NUMERICALLY LOWER RATIOS (2.2:1, 2.76:1, etc)--2.76 turns of the driveshaft = 1 turn of the axle

SHORTER (lower) gears are NUMERICALLY HIGHER RATIOS (3.91:1, 4.10:1, etc) 4.1 turns of the driveshaft = 1 turn of the axle.

you might have come up with your own definitions, but sorry, this is just how the rest of the world defines them. if you don't believe me, just google "tall vs. short gearing" and see what you come up with.

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Another consideration is the 3000 rpm stall speed of the converter. I know that this car can never be a fuel sipper, but I wonder if I need to target a freeway rpm somewhere near the stall speed to avoid cooking the trans? The 3.23 set spins the motor (Or the other way around) at about 2600 at 65. Maybe the "final drive" with the GV should be near 3.23. With this in mind, the GV has an OD ratio od .78. The 4.10 X .78 is 3.20 while the 3.91 X .78 is 3.05.
What are your thoughts on cruising UNDER the converter stall speed? It seems that the motor might act a little lazy and inefficient.

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my understanding is that a GOOD converter, it won't matter. it'll only slip when you're giving it lots of torque. so part throttle cruise down the highway and it won't slip much.

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a good high stall converter won't slip significantly more below the stall speed than above. stall speed is the RPM of max torque multiplication. a "tight" high stall converter with tall gears is a good compromise, especially if you have a torquey motor. Pete, who works at XV (I think his moparts handle is GmachinedartGT) has a killer combo running a tight, high stall converter behind a 408 and 2.94's...highway cruising is comfortable, and it'll still crank out low 12's in the 1/4....

I had 3.55's with 27" tall tires and HATED it, buzzing along at ~3300 RPM at 75moh on the freeway got old after about 20 minutes. I put an A500 in and kept the 3.55's. if I didn't have the option of an OD tranny, I wouldn't go more than 3.23's, possibly even 2.94's, depending on tire size.

and Doc Fiberglass, yes I was talking about rear gears, too.

TALLER (higher) gears are NUMERICALLY LOWER RATIOS (2.2:1, 2.76:1, etc)--2.76 turns of the driveshaft = 1 turn of the axle

SHORTER (lower) gears are NUMERICALLY HIGHER RATIOS (3.91:1, 4.10:1, etc) 4.1 turns of the driveshaft = 1 turn of the axle.

you might have come up with your own definitions, but sorry, this is just how the rest of the world defines them. if you don't believe me, just google "tall vs. short gearing" and see what you come up with.

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