1. #1
    that is my question.
    84 stock cj7 and on the 65/70 mph highways it takes everything it has to keep it up to speed on inclines and because of the sheer wind force lol.
    any simple mods i can do to give it a little more at high rpms would be appreciated.
    (I plan on converting to a k&n very soon to let it breathe easier)
    84 cj7 in middle of motor swap,TBI,borla and all kinds of goodies
    79 z28 deep in restoration mode
    69 corvette t-top black/black L46 4 speed 52k original miles,frame off restored councours show winner

  2. is it a 258?
    how many miles?
    my 84 had lost a lot of power before i had to rebuild the engine. you might want to check the compression on the cylinders, there may be a weak one.
    since the rebuild, i can run 70 and still feel the engine pulling as it accelerates, but 70 is really faster than i want to go in it

  3. Try taking your Jeep up a hill (incline) were it´s just holding it´s own. The RPM´s arn´t really going up or down, with pretty close to full throttle. Retard the timing a couple of degrees. Try the same hill again. This may decrease Your peak RPM´s some, but may make it pull better at mid range.
    K&N is probably a good, idea.

  4. #4
    its at 160,000 but engine was rebuilt at 140,000 and transmission replaced last month with a jasper's t-5.
    its probably more due to me being used to my z28 and being able to break traction at 70 than anything else lol
    i just need maybe 25 more horses....it has torque for days heh
    maybe putting in an accel ignition then k&n air filter and replacing exhaust(which i need to do next,its overdue) with more efficient cat and muffler will cure it.
    84 cj7 in middle of motor swap,TBI,borla and all kinds of goodies
    79 z28 deep in restoration mode
    69 corvette t-top black/black L46 4 speed 52k original miles,frame off restored councours show winner

  5. Hello Sacredgroove,

    I have a nearly stock 85, CJ-7 with an I-6, T-5 and 33-inch tires. On anything but almost level ground or going downhill, the 5th gear (An overdrive gear.) is essentially useless.

    The minor mods I found effective were the "Nutter Bypass" and replacing the original distributor with a GM-HEI ignition. (State smog equipment inspection laws vary...so first investigate your state smog laws-regulations.)

    Those two mods were both low-tech and low-cost, but made a substantial improvement in overall performance. Even with those mods, however, I have come to accept that an old Jeep with much larger than stock tires and the aerodynamics of an outhouse is going to be something of a dog at highway speeds. (Air resistance varies as the square of speed???)

    That lack of high speed performance is not a problem for me. I drive the CJ because I enjoy it...a lot! If in a hurry, I use another vehicle.

    There are many possible mods Most of those mods, some of which are probably actually effective, will push you toward the world of high tech, high labor and high cost.



  6. Cheap obvious fixes are to change the filters(gas&air), even to a stock one. Made a world of difference on Sully's CJ7. After that we rebuilt the carter, better still but the biggest improvement was a clean air filter.

  7. Hello brian4.2,

    I can certainly see why keeping on top of air filter maintenance would be important in your locale.

    In several of the Miller Jeep Run pics (great pics!!!) posted by Sully, the Jeeps appeared to be driving through dust clouds.


  8. #8
    Join Date
    Jul 2003
    Fayetteville Arkansas
    70?? Try 55-60mph Jeeps like it there much better. Unless you have tall tires and or gears 70 is screaming. Not to mention scary in any CJ series. I have a 79 with 31's and 3:73's and T-18, 60 is perfect cruise. The engine redlines at 4200 hundred running at 3+ isn't doing it any good. Max horse power is reached at about 3200, maybe lower. Although mine will pull past 70 without much complaint I don't leave it there.

    Ok now to the answers you wanted to hear. I agree retard the timing a bit. Try it out and see if you can live with it. Go with larger tires, but you'll lose some low end torque. Taller gears but the Jeep gods might curse you forever for a gear job for highway speeds.
    Check the obvious filters as mentioned before. Check compression, and fuel pressure. And last but not least get a Honda for the highway.

    79 CJ7

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