Technical Trifive Gasser Steering Boxes & Arms.

Same as the Aisin Box I used in my Corvette, except I used an external mounted RHD Mitsubishi version to sit inside the rails on my LHD Corvette.
The outside dimension are almost identical to the Corvette box ,but slightly longer on the column side to allow for power steering hoses. [I simply tapped the collapsible column up a bit]
The Rag Joint off a Mitsubishi L300 Van that literally bolted to the Corvette upper half [I had to file the safety slots slightly wider on the Corvette upper.

I chose the Mitsubishi Aisin box for the 16:1 ratio [quick steer] and internal power steering and ditched the old Corvette ram system
If anybody reading this is considering an Aisin Power steering box, please vulture the hoses while you are at it. The hoses have internal flow restrictors in the [1 in pressure, 2 in return]
Also the top of the box has 2 little arrows cast in them to show flow direction

Aisin makes steering boxes for most Japanese makes.[and now aftermarket]

@1971BB427 good on ya for scouting junk yards , that's what Hot rodding is all about

 

This 525 box is looking better & better!

 

Had to search for this Mitsubishi box, but found it on 1992-2000 Monteros. Only issue is these are all power steering boxes as far as I could see? Power steering is great, but not something I've ever done on a gasser build. So not sure I'd use the Montero box unless they make a slower ratio manual box?

 

Try Dodge D50 / Mitsubishi L200 pickup or Dodge Challenger / Mitsubishi Sapporo
Or any RWD Mitsubishi Galant / Chrysler Sigma

If shipping wasn't so expensive ,I could give you some we throw them out. We only want the 16:1 power steering box for road racing.

In Aussie and NZ we use the Datsun 260C for RHD power steering conversions on 55-57 Chevys [but they are all P/steer] so I looked further.
Try a Datsun 720 pickup steering box [early models were non power steering] or Datsun 180B

 

Another advantage to using a 525 box is the variety of pitman arms you can choose from (since they were used on so many applications) so the drag link is parallel. I used a 64-67 chevelle arm without having to bend or modify.
Drag link and tie rod are 1" DOM with 63-67 tie rod ends.

 

'57 Chevy, 2 dr. Sedan, Blown BBC.
What size rectangle tubing for the sub frame? I have 2" X 4", 1/8th wall but it looks a little wimpy, should I jump up a wall thickness to 3/16th.?

 

2" x 4" x 1/8" wall is more than strong enough.
Most Car hauler trailers have that size for main frame rails [with a heavy car straddled each side of the central suspension mounts.]
If you look at your photo above [and here] the suspension loads are transferred via 4 points. [2 are attached to the original frame]


If your car weighs 3600lbs with 50/50 front to rear bias that = 1800lbs on the front.
The extreme ends [front] with maximum leverage need to support 450lbs

You also need to lower the rear hangers by using mounting plates so the springs are a lot higher in the front.
That way the axle will arc rearwards [red arrow] to counteract the spring lengthening as it is compresses [yellow arrow]


This minimalizes wheelbase changes with suspension compression [and roll steer]

 

The wheelbase changes from spring compression are so minor it's really not worth worrying about. If you ever compressed the springs hard enough to even get 3/4" movement you're probably going to have bigger worries than wheelbase changes.
And if you put the shackles front or rear it's not going to change how the springs compress. I personally don't put shackles on the same side as the drag link so the drag link doesn't push/pull against the shackles. But if shackles are kept short around 3" eye to eye, and made of good bar stock then even this isn't an issue.
Roll steer shouldn't be an issue either unless your springs are fairly soft. The average spring packs used in a solid axle build don't allow as much body roll as any A arm coil spring front setup.
Not sure how you'd ever get 54" springs under the front of a Tri Five Chevy? The front mount will likely be way out beyond the bumper! There isn't 27" from axle center to the bumper on a Tri Five.

 

1971BB427, I think Kerrynzl's drawing above was intended as generic? Just like you I always appreciate all of you taking the time out of your day to respond to Hammers questions. Just trying to tack weld in sub frame & mock up axle and wheels/tires to get a feeling for where "things" like shackles & steering box will be mounted, easier for me to go to "A" to get to "B" than "C"!

 

You get it! [The drawing was generic]

Also the term "Roll Steer" is a term suspension designers use to differentiate from "Bump Steer" they both are different.

 

Thanks. Thought maybe that was the case on the generic drawing.
And I know bump steer from roll steer, as body roll raises or compresses the springs which can shorten the distance from steering box to front wheels. But still doubt a firm suspension as parallel leafs in a gasser use will have any roll steer issues. At least I've never experienced it in numerous solid front axle swaps I've done.
I try not to have bump steer either, and get my drag links as close to level as possible.