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81cj
08-16-2004, 06:38 PM
need some help. I'm trying to decide what gears to run in my cj. 81 cj-5 304, t-150, dana 20, 33 tires. according to online calculators if I go with 4.10 S @ 55 mph I'm turning 2300 rpm's. thats a 600 rpm increase over what i was with 2.73 and 31s. anybody have an opinion of that rpm on that 304 ???????? 111!!! :-|

tufcj
08-16-2004, 09:29 PM
If you do a lot of highway driving, go with the 4.10s for mileage. If you want some more power, or EVER plan on going to a bigger tire go to 4.56s (just about everyone upgrades even when they say they won't :roll: ). Since installation and gears are expensive, figure out what you'll be doing, and only spend the money once. I went 4.27s with 35s when my Jeep was a daily driver. I went to 37s last summer, and the 4.27s aren't enough any more. I've got a set of 4.88s waiting install in the garage.

With the 4.27 gears and 35" tires, I ran about 3200 RPM at 75 on the highway. I drove my Jeep on several 800+ mile trips and one 2000+ mile trip with no problems. My Jeep is a 360, it won't hurt a 304 to rev the same.

Bob.
tufcj

cheapjeep
08-16-2004, 09:54 PM
I put 4:10s in mine with the same setup you have. I run 32x11.50s on 7 inch rims so they are as tall as 33s. It is a little ruff on the clutch taking off in 1st gear (not as bad as the 3:55s though) For me the 4:10s work good for an all around gear. I get about 10mpg anyway so I don't worry about the rpms.

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