no, you need an idler arm/center link of some type. It has to do with the arc that the spindle moves, you need the steering linkage to follow the same arc, to prevent bump steer. A solid axle doesn't have this arc, so you can use a single tie rod, and a drag link.
I put a rear steer rack on an old Hudson Jet...it doesn't act right...I see the pivots on the Omni rack do not align with the pivot on the lower A arm,which are very long,longer than most a arm cars I've seen...may be wasting my time.The original steering was a worn out center pivot that interfered with my engine swap.
They don't always line up [especially when looking at it] With unequal length A-arm suspension they try to minimalize bump steer within a range of motion [usually 2-1/2" compression and 1" rebound] Here is a basic schematic You can see that if the car was lowered the bump steer needs to be looked at again. [because the range of motion changes] Engineers aim for dynamic Toe-in bump steer on extreme compression and Toe-out on "droop" or extension [because of tyre loads] Toe-in is my stable than Toe-out. Now look at the above "theoretical" bump steer schematic...... It is ******** in reality because the tie-rod in this schematic would be shifted over to the left to allow for Ackermann [the curse of race car steering ] AND the whole Tie-Rod would actually be lower because the spindles have positive caster [ from a side view the steering arms are perpendicular to the king-pin axis] Steering geometry is not for the novice. My advice would be put the old steering system back into it . The if you want a Rack, then measure the centre link between both inner ball joints [at the actual ball joint centres] Then go looking for a Rack that has similar inner end measurements . When you mount the rack try and get it on the same horizontal and vertical plane as the original centre link. You need room to "shim" the rack up/down to adjust for bump steer.[Make a bump steer gauge from plywood] On a rear steer steering if you move the rack [or centre link] forward will increase Ackermann , and rearward reduces Ackermann. On front steer the opposite applies. Don't overthink Ackermann , this is the domain of "Carpark Queens" ,because at higher speeds tyre slip angles come into play and negate the effects of Ackermann You cannot go wrong with removing moving parts to add reliability , and simplicity
From the way back memory... A late 1990s or early 2000s Chevy Cavalier has a steering rack with the inner pivots at the center of the rack. You could get those racks as power, or non power steering. A Dodge Intrepid (93-99 maybe newer) used the same style rack. The difference between the two racks were that one was a rear steer and the other was a front steer (the tie rods interchanged as a set between the two racks). I can't remember for sure which was which, but I'm thinking the Dodge was the front steer rack. Both racks had very long tie rods on each side (longer then you will need). A qualified welder should be able to shorten the tie rods to the length you need. If you still have the tie rods from your car hanging around, you can probably make a center piece to bolt to the rack inner mounting points that extend to the location you would need to mount your car's tie rods to the "new" center link. Or maybe you could modify your car's tie rods to accept the inner tie rod ends for the rack. Years ago, I put one of these racks on a 46 Plymouth coupe. I modified a set of Intrepid tie rod ends (I had them, but the rack was the wrong steer style) that were very close to the correct length of the old Plymouth tie rods. The rack worked out pretty good, but as I remember, it has a slightly larger turning radius then the original steering box had. The rack I used was a power steering rack coupled to a Mopar power steering pump. At 80 mph, that steering was a bit touchy (probably had too much pressure), but there was no noticeable bump steer. Might be another option.
How exactly did the engine swap interfere with the stock centre pivot? Oil pan? If so, are there other oil pan options for your engine? Without that info it's really impossible to know what exact real estate you've got to work in. The stock A-arms appear to be swept back some, so that the arms' axes cross at points behind the axle line. The stock centre pivot doesn't sit exactly where the diagram @Kerrynzl posted suggests it ought to be. I wouldn't be surprised if the stock steering produced a bit of toe change in bump, little enough to be acceptable to the factory. That might have been about keeping the centre bell crank simple and therefore cheap to make. If you've got CAD capability it would be simple enough to insert the above jpeg as a raster image, trace the geometry, mirror that to include the other side of the car, then draw in any candidate setup you've got in mind. Plot the steering motion at three or four input angles. You can use the section at bottom to check bump motion — roughly, as it looks like the section is taken at right angles to the A-arms' pivot axes. I'd guess that the centre link joint wants to be directly behind and a touch to the right of the lower arm's pivot axis, but you'd need to project that back to the plan view. I see that the steering arm on the spindle is a bolt-on part. The section at centre right shows a tapered shaft with a keyway. Custom steering arms might not be beyond the realm of possibility, if they end up being needed.
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