Gear Ratio Question

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Dec 31, 2004 | 02:03 PM

Tepot

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Gear Ratio Question

HI,

I've swapped my inline 6 with a V8 302 recently. Now I don't like my gear Ratio. I need quicker response when I put the pedal to the floor.

I don't drive offroad with this truck. I only drive on highway.

So I have a V8 302 with a Mazda 5 speed Overdrive manual transmission. I currently have 3.08 gears and running on 35" tires.

What should I go with that will give me more power on demand but not too much lost for gax millage?

some said to go in the 3.55 range, some said in the 3.70 range, and some even told me to go with 4.10 gears.

What should I do?

Thanks

Dec 31, 2004 | 05:18 PM

SoCalDesertRider

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From: USA

Since you have an overdrive gear in the transmission, 35" tires, and the 302 engine likes to rev, I would go with 4.56 gears. 4.10 is the minimum gear ratio I would go with that combination. It's the combination of 35" tires and 3.08 ratio that are killing your power.

Dec 31, 2004 | 05:55 PM

MustangGT221

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From: Topsfield, MA

I wouldn't go with a 4.56, too high. The Mazda tranny's OD ratio is only .80....the automatics have a .70, the ZF has a OD ratio of .78....I always recommend a 4.10 for the M5OD, and a 4.56 gear on the auto's w/ OD (using 35" tires).

I ran a relatively stock 302, 35" tires, 4.10 gears...and found it to be the perfect match, it's a little conservative for hwy gas mileage...but still has a good gear ratio for power.

I can't believe how awful the power must be running 35" tires and only 3.08 gears, I ran 3.55 gears on 35" tires for 2 months and was ready to rip my hair out. Putting in the 4.10s made the world of difference.

If you were able to use a 4.30 gear, a 4.30 gear w/ 35" tires...is the equivilant of 3.55 gears on the stock tires...which was a good ratio, 3.55 is what usually came on these vehicles from the factory...so 4.10 vs 4.30 is pretty close. I've found that the 4.56 is just a tad too high for a lot of hwy runs....

I'm changing my transmission to a ZF, which has a slightly better OD ratio, so my 4.10s would be a little under what I need, and 4.56s would be better, but I'm going to be running a 400 hp 393 so I think it'll be fine. I'll see how I like the 4.10s/ZF trans, I may go to 4.56s when I put the bigger axles in there. For now, the 4.10s are staying.

Jan 1, 2005 | 11:40 AM

Tepot

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Thanks guy's

This was very usefull information. exactly what I needed to know. I'm gonna go and order 4.10 gears right away and I'll let you know how it turned out.

Thanks

Jan 1, 2005 | 01:26 PM

yield2s

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you think your bogged down. My 77 f-150 351m/3spd auto 4x4 has 2.47 in the back and 33"s.
Getting matching(to the front) 3.50 in there as soon as I can drive it down to Hoopers rearend.

Jan 1, 2005 | 01:59 PM

Tepot

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Hey MustangGT221,

With my 302, 4.10 gears, 35" tires, what is the top speed in KM\H will I be able to get on Highway? I know the 4.10 will give me more power, but will I still be able to reach the 140 KM\H mark?

The Max speed here in Canada can be a 100KM\H or 110 KM\H on highways. If I wanna pass a car that goes 110 KM\H. Will I be able to pass him easily or will I be already at my top speed?

I know it's a hard question. but since you have that setup on your truck already, I tought maybe you would know.

Thanks