Other Power Steering Box Options for a '40 (1 Viewer)

Joined
Apr 20, 2020
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7
Location
Pacific NW
Newbie here with some questions for y'all on "other" power steering box options for an FJ40...

I've sorted through a bunch of the existing posts and haven't found anything specific to the options I'm asking about - Please if they're there, and I've missed it, point me in the right direction!

I will be starting my build soon and I'm beginning to collect parts in an effort to get it together sooner, rather than later. Right now it's a rolling chassis with SBC/700R4 combo but I'm switching to 4.8LS w/4L60E out of a Sierra 1500 (bought the whole donor truck as a driver.) I'll be doing a shackle reversal and small (2.5"-4") spring lift. I know the shackle reversal seems to be somewhat... controversial? here, based on what I've read.

All that said, I've been reading up a lot on the PS conversions and different routes people have gone. Here is where I'd like some input from people that have been here before... I'm looking at two possible alternate candidates for the boxes:

The first one is a stock GM box off a GMT800 platform ('99-'06 Silverado/Sierra 1500). This box is readily available, priced well and plenty of parts and support. Additionally, it's what my engine's pump is already mated to, valved correctly for, and has the right fittings (no standard/metric conversions, etc.). I would place the box in the front frame horn like the other Saginaw conversions, and run a cross-over steering to the passenger knuckle, maybe even high-steer arms, if needed. The box is only a three-bolt mount but I think that should be more than sufficient, given the weight of the FJ vs. the full-size it was designed for. Orientation of the steering arm is correct and it's a roughly 3.25 lock to lock box (I know some people say a 4-lock box is better).

GMT800 box:
Chev.jpg
Chev2.jpg
Chev3.jpg


Another option I've considered (but not as thoroughly), is a 2013-2018 Dodge 2500/3500 4WD box... This is also only a three-bolt mount but, for the same reasons I listed above, I don't have any concerns with this arrangement. One thing I do like about the Dodge box is the factory steering shaft already has an extended shaft so there would be no reason to use any spud shafts to make up the difference through the front crossmember.

Dodge box:
Dodge.jpg


Dodge4.jpg


As far as mounting, I've got the fabrication skills and could whip up a mount to bolt it to the frame, so I'm not concerned there. This is all very preliminary and I still have some mocking & measuring to ensure I can make it stop to stop on the axle with either of these options. One think I haven't worked thru (yet) is the tie rod ends, and there variations thereof, for the steering/pitman arms and such. If it ends up being a real PITA, I could always go with some good Heim joints. Additionally, I haven't confirmed if the Dodge's steering shaft works on the GM box (same size/arrangement)... I'm gonna guess it's not for now.

My Cruiser will be primarily a semi-daily driver and light trails with snow/mud/dirt, etc. exploring the Northwest - No immediate rock-crawling plans for me (yet) :).

Anyone have any thoughts or experience with the boxes?
Thanks!
 
Joined
Oct 16, 2019
Messages
24
Location
Truckee ca
I have done several saginaw conversions using 4x4 labs kits. Beefy, easy and reliable, but not cheap.

Another route to consider is using an 80 series box
 

GRM

Finding new adventures in old jalopies.
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Joined
Nov 19, 2003
Messages
1,156
Location
Livermore, CA
I prefer a 60 series or an 80 series box too.

That dodge box is big, but beefy. I believe it uses the same bolt pattern as the Saginaw or the GMT800 box. Its big. I personally just don't like having a steering box sticking out in front of the grille.

Although, if your going to use a saginaw box, my favorite is the 4-bolt Jeep Wagoneer or J-series truck box.
 
Joined
Jun 5, 2007
Messages
5,159
Location
Brea, Calif.
1. The guys who like 4 1/4 turn Saginaw gear boxes are the guys who like mushy steering on the highway, 3 1/2 turn box has a better ratio, and gives a much better highway feel.
2. I would not worry about a 3 bolt box, cripes, when Chevy used 4 bolt boxes they only attached some of them with 3 bolts, then they went to 3 bolt boxes on the newer stuff.
 

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