Engine advice...need more torque

Jan 22, 2009
Huntsville, AL
I have a 93 fzj80 with 240,000 miles on it. It is absolutely bombproof, so reliablity is not the question. My problem is that is seems to have lost some power. Now, I understand that with only 212 bhp out of the factory, they weren't exactly overpowered to begin with.

Anyway, Cruisers are heavy and are only going to get heavier with the build up, so I need more power and torque. I would really like to keep the original engine...so any ideas?

Here is what I am thinking now:
  • Exhaust system and high flow cat, or no cat at all, to let her breath easier. maybe new headers...
  • K&N Air Filter
  • Total engine refresh
Any other ideas? I have heard there are no superchargers left and there is no way I am putting a turbo on it. I have already decided to change to a 4.88 gear ratio.

On more thing...as a last resort I might decide to convert to either a 350 or diesel. Has anyone done a diesel conversion? Is it possible to find a cruiser diesel engine in The States? How about putting a Powerstroke in it, is that possble?

Thanks in advance!


Wheeling in scale
Aug 30, 2006
Stay away from the K&N. They do absolutely nothing, that's from personal experience.

Regearing to 4.88's will help you with power, but you'll lose some top-end (higher RPMS on the freeway). If that's not an issue, then go for it!

As far as diesel swaps go, a common one is the Cummins 4BT. Around 100 HP, 270 lb/ft (something like that, I can't remember actual numbers).
Nov 14, 2008
Alton, IL (near St Louis, MO)
X2 on the K&N, have used them off and on for years and for the most part found them to be just a hit to the wallet. Only exception being a few sports cars, just seat of the pants but seemed to have a slight increase in throttle response.

There has been a few articles I have read that also questions the amount/size of particles allowed to "flow" through. Who really knows.

In the end I feel that putting $'s towards a tuneup and or fixing/ replacing anything that is broken, is the best bang for the buck. Particularly with an older higher mile truck like ours.

Just my 2 cents


Retired LC Parts Professional
Aug 28, 2004
Woodstock, NY, USA
Considering the mileage that your rig is at, you are pretty much at the point of a designed-in rebuild point.

If you want more power--and you want to keep the 1FZ-FE (which I agree with you on)--then I would pull the sucker, rebuild it, over bore it, and redo the top end while you are at it as well.

Re-gearing, as mentioned, will get you more abilities on the low side, which is generally what we all want. You'll be pushing 3K RPM's at highway speeds, but the 1FZ can easily handle this.

If you want another option--buy one of Rodney's low gear boxes from Australia and install it.....

Anyway, good luck.
Dec 25, 2008
High Point NC
I would be inclined to do a diesel conversion with either a Cummins 4BT or a 6BT. The easiest way is to go with a mechanical engine but I want to at some point go with a 2nd generation Cummins 5.9 liter. With the right components you can pull 350hp from the small 4BT and the HP and torque from the 6BT is only limited to your wallet and how well you want it to behave on the street. You always have to consider when you upgrade power that you have to at some point upgrade many other components of the truck to be strong enough to accomodate your new found power.

Best of luck!!!
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