I know there are a a bunch of posts about this but I want to see who has a similar set up and if they wish they would have done it different. I am wanting to switch from my 4.10's to either 3.73 or 3.42, I have a TH350 and 28" tires, the 4.10's have become too much of a pain for 50mph and up. Will the 3.42's really hurt it on the streets or is 3.73 the way to go? Mainly street driving with occasional highway travel, like 20 minutes of freeway time at most. Thanks
Gears, 3.73 or 3.42 opinions
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Gear swap
Instead of switching gears,switch out the Turbo 350 for a 87-91 200R4, the lower first gear will launch harder off the line and you will have a substantial reduction of RPM's for highway cruisin'.Based on the Turbo 350 at 4,000 RPM the 200R4 would drop RPM to 2680 in overdrive.
Instead of switching gears,switch out the Turbo 350 for a 87-91 200R4, the lower first gear will launch harder off the line and you will have a substantial reduction of RPM's for highway cruisin'.Based on the Turbo 350 at 4,000 RPM the 200R4 would drop RPM to 2680 in overdrive.
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I recently switched from 2.41s to 3.73s in my cutlass with 28" tall tires and a th350 trans. Big difference. This winter i am throwing in a 700r4 for the overdrive and the 3.08 first gear 
If u want to keep your 3 speed tranny i would go with 3.42s. even 3.73s are tough on the highway. But like jeff b said it might be easier to go with an OD trans. Not only does it have the over drive it also has a lockup converter.
If u want to keep your 3 speed tranny i would go with 3.42s. even 3.73s are tough on the highway. But like jeff b said it might be easier to go with an OD trans. Not only does it have the over drive it also has a lockup converter.
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i have a set of 3.42 gears for a 10bolt and 12bolt. ive been looking for 4.10 gears for a 10 bolt so if your iterested in trading let me no thanks
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2,233 Posts
If you do most of your driving ON the road, go with the 3.42 gears, if you an every weekend in 4WD go with the 3.73.
I ran several different trucks with 235/75/15 tires and 3.73 gears, ran a few others with 31 inch tires both manual and automatic and never really thought too much about it back then.
Right now I'm swapping a TH700R4 out for a SM-465 manual in my 1988 SUburban with 3.42 gears, and with the price of gas now I am sort of considering swapping a set of 3.08 gears out of a spare axle I have here to make up most of the difference in losing the overdrive.
I ran several different trucks with 235/75/15 tires and 3.73 gears, ran a few others with 31 inch tires both manual and automatic and never really thought too much about it back then.
Right now I'm swapping a TH700R4 out for a SM-465 manual in my 1988 SUburban with 3.42 gears, and with the price of gas now I am sort of considering swapping a set of 3.08 gears out of a spare axle I have here to make up most of the difference in losing the overdrive.
This will be for a street car, its a 71 Nova, 10-Bolt, 8.5 rear w/posi. it also has 28" tall tires. Does anyone know if there is a gear between the 3.42 and 3.73? Someone told me there was one in the 3.50's but I have yet to see it. Thanks.
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