highway speed (lack of it)

[murf]

I've got a 92 4X4 with the 2.9, 5spd, 3.55 gears and 31x10.50 tires. When I take it down the highway, it tops out around 78 on the speedo unless I'm going downhill or have a good tailwind. If I have to get over a hill (any slope or distance) the speed drops to around 55 unless I put it in 4th.

Any ideas as to what I can do to improve performance? I'm getting tired of trying to push my foot through the firewall.

thanks,

Murf:annoyed:

[baddis]

regear i am running 31x10.5 with 4.10 and it comes out to 3.56 mileage sucks a$$ because i have no overdrive right now but it will be fixed soon

[rickcdewitt]

that sounds about right for a 2.9l,a little more power than a 4 banger but not a lot.its a small engine you'll need to compromise with gears to get grunt.there are more trucks with 4.10's than you might think,a junk yard swap would be a lot less than buying gears for your truck and having them installed.the diff tags will tell you whats at the wreckers.if you want your speedo to be close run 3.73 gears,they'll give you the same ratio as stock tires and the 3.55's.you'll need 33's with 4.10's to have the same ratio but i'de reccomend just changing the speedo gear and gearing down,my truck doesn't like factory high gearing with lift and big tires.with 4.10's and 31's you could probably use the speedo gear from a 3.73 truck to get close.

[2manyfords]

Ya thats sounds about right for a 2.9L with that gearing and tire combo.

Just drive it in 4th on the highway. Your mileage will likely improve and it won't hurt the engine in any way.

[Hahnsb2]

I've got a 92 4X4 with the 2.9, 5spd, 3.55 gears and 31x10.50 tires. When I take it down the highway, it tops out around 78 on the speedo unless I'm going downhill or have a good tailwind. If I have to get over a hill (any slope or distance) the speed drops to around 55 unless I put it in 4th.

Any ideas as to what I can do to improve performance? I'm getting tired of trying to push my foot through the firewall.

thanks,

Murf:annoyed:
With 31s and 3.45 gears I really couldnt use 5th at any speed... Remember, add about 10% to your speed if your speedo is uncorrected, 78 is actually more like 86mph. Use 4th, ESPECIALY on hills, even with 4.10s I almost always use 4th on hills, its easier on the engine to let it rev out a bit. A good solution is to find a set of 4.10 axles... BTW going slightly downhill my B2 will top out at 92mph with 4.10 gears, so you're not that far off from me...

[murf]

I thank all of you for the info. I was thinking that I needed to chg the ratio in the rear and you confirmed it.

Now, all I have to do is find another rear end and get it put on the truck. Although, rusty bolts are kind if making me nervous. I might have to invest in a compressor and inpact wrench before I start putting this much into the truck.

Later,

Murf