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Discussion Starter · #1 ·
If putting fj55 springs in place of 40's on a 40 will there be any additional lift?
If so how much, if less how much?
thanx.
 

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It depends....(how's that for vague?)

FJ55 front springs are identical to FJ40 front and rear packs in their length and arch.

FJ55 rear springs are 3.5" longer with a centered pin. Arch is comparable, tho the packs are thicker (8 leaves stock).

If you are installing the front and rear packs from the FJ55 into your FJ40, there will be "no" height difference. (and why waste your time with the front FJ55 packs, IMO.

If you are installing 2 sets of rear FJ55 packs, then yes, you will gain about 1" in height. This is because proper mounting of the front packs requires the shackle to be located further down the frame at a lower point, raising the truck height. Also, for proper spring orientation, the front solid mount should be a bit lower than normal as well, about 1". In the rear, you can use a longer shackle to level things.

I had to rework my front springs with an additional leaf to maintain any positive arch...9 leaf front and 8 leaf stock rear.
 

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Discussion Starter · #3 ·
my current plan is to run 55 rears in the rear of the fj40. And reverse the fj40 stockers up front - actually this is done already. The front has the shackle reversal too - using stock type shackle mounting heights and locations.
If I understand you correctly you recommend using the 55 rears in the rear only - right?
And for the front will the reversed stock 40 springs suffice. This is SOA and I plan to run 39.5 swampers (actual OD is 38") and trim the body as much as necessary.
your thoughts are appreicated.
thanx.
 

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Actually, I recommend using the 55 rear leaf springs all around....their greater length provides additional travel possibilities.

Running the FJ55 rear packs in the rear of your 40 will lengthen your rear drivetrain by 3.5" and require you to "spin" the shackle mount around. Longer rear driveshaft is required and a anti-wrap bar is highly recommended. (either that, or practice replacing centers due to snapped pinions)

Switching from your current FJ40 front packs to FJ55 REAR packs will move your axle 3.5" back, shortening your front driveline. Final result will be a 93.5" wheelbase.

Keeping your current front springs and exchanging the rear springs for the 55 packs will net you a 97" wheel base. (stock is 90", reversing front springs = +3.5" and reversing rear springs = +3.5")

When I originally installed my setup, I ran the rear 55 packs in front, keeping my axle at approximately the stock position (+.5"). I then installed stock FJ40 packs (+3.5") in the rear, but reversed them and used a 1" lift block to level the truck. Once I located a 2nd set of rear 55 packs, they dropped right in and allowed me to ditch the lift block. I now have a 94" wheelbase.
 

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Originally posted by woody:
[QB]

Running the FJ55 rear packs in the rear of your 40 will lengthen your rear drivetrain by 3.5" and require you to "spin" the shackle mount around.

Switching from your current FJ40 front packs to FJ55 REAR packs will move your axle 3.5" back, shortening your front driveline. Final result will be a 93.5" wheelbase.

Keeping your current front springs and exchanging the rear springs for the 55 packs will net you a 97" wheel base. (stock is 90", reversing front springs = +3.5" and reversing rear springs = +3.5")

QB]
I run the 55 springs out back only. And I did not flip the shackle hangers. All I did was get 2.5" extended shackles. They make a very nice 45deg angle this way...

So my setup is 55 springs in the rear with the reversed 40 springs in the front. Seems to flex really well... Espically because I removed some of the leaves out of the spring pack in the front and rear...
 
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