CJ5 gearing

[murphystoys]

Ive got a 1975 CJ5 with a mildley built 258 6 cyl. 3 speed Holly 4 bbr carb I need to know what gearing I need to go with for highway running. Its got 33" tires on it now the motor is very strong but itll only run about 55 to 60 mph on the highway taching 3000 rpms. Does anyone have any suggestions?

 

[mmcj7]

Is that 55 to 60 by the speedometer? Because it may be wrong since your running 33" tires.

 

[BigBody79]

It looks like you have around a 4.56 or so in there now. You could drop that down to a 3.73 and you'll be running about 2300 rpm at 60mph

http://www.4lo.com/calc/gearratio.htm

 

[mbalbritton]

on a side note, I'd recommend ditching that Holley 4brrl. that's too much carb IMHO. heck it's a lot for a 304.

 

[murphystoys]

Yea the speedo is right and yea on the carb does anyone have an opinion on what carb I should run?

 

[mbalbritton]

If you're going Carb on the 258, then hands down MC2100.

Pick them up in the junkyard for $30 and then get a $30 rebuild kit. Stupid Easy to rebuild.

 

[RenegadeT]

so you think you have 4.56 gears in there? I'm sure you could find someone with 3.55 axles and do a complete swap. If I had that problem, I'd try 35" tires.

 

[49willys]

If it were me i think I'd try to find a 4speed tranny and go to 35's.

 

[strange1]

i got some 3.55 gears. cheap.

 

[mmcj7]

I got some I would trade. 3.55 gears from a 1976 cj5.

 

[RenegadeT]

If it were me i think I'd try to find a 4speed tranny and go to 35's.

a 4 spd has the same 1:1 final ratio as a 3 spd, a 5speed overdrive would be a better swap for highway driving. Too bad all CJ 5-speeds aren't very heavy duty..