The stock K is just stamped metal. If you remove a significant portion of the lower stamped piece so a rack fits through, you've weakened it. The structure needs that bottom panel for structural integrity. The K is just like the unibody design of the rest of the car. You wouldn't cut out the floor panel and wonder if you've weakened the car. If you post a picture of the bottom side of that K frame then we might have a better idea of how bad it is. Maybe it's not that bad, hard to say without seeing it.
If you're aware of the Ackerman and bump steer issues, and you still want to run it on the street 5% of the time, shame on you. A car with Ackerman issues like that one has shouldn't be on a public road. The fact that it's been done before isn't an excuse.
A lot of drag racers have done a lot of really dumb things and gotten away with it. Some of them for a very long time even, but the fact that all of them didn't die isn't proof something is a good idea. If you always drive in a straight line, the Ackerman issue isn't so terrible. If you never hit any pot holes and only drive the car a 50 miles a year in 1/4 mile stretches and an occasional trip to Dairy Queen you might not flex your K until it cracks for quite awhile. Start using it on the street with regularity and stuff will start breaking. Just because something works on a drag only car doesn't mean it will work on a street car, and it certainly doesn't mean it will be SAFE on a street car.
Just responding in regards to weakening the k member. In regards to that I chatted with the individual on here that did the dakota rack and pinion swap. and it mounts very similar to how this duster is setup. I don't see how that weakens it?? Again this is a 95% of the time drag car and I am aware of the ackerman angle and bump steer.
I understand that this is far from stock but lets face it drag racers have done this for years with these cars. Not saying they are the exact setup as this duster but they are very similar.
I agree with 72blu and for the record, there’s very few on this site I would trust when it comes to suspension and steering questions and 72blu is one of those.
but I am going to add this, not only shame on you, but you need to consider worst case. If you drive that thing on the street and have to swerve to avoid an object in the road, and those Ackerman issues flare up resulting in you or whoever driving losing control and hitting someone else, injuring or killing them. Or that K frame breaks and sends you into oncoming traffic. Insurance is going to inspect those cars, if they see you hobbled out the K frame and stuck a rack in there in that fashion, they’re gonna start digging deeper. You, as the builder, would be legally liable and possibly criminally. I used to work for one of the big three Insurance companies. I have seen this play out before.
it would cost you just a couple hundred to convert that back to factory with a replacement K frame with factory manual steering and not affect you on the strip at all. But it could not only save you headaches in the future, but also could save someone’s life.
Build a drag car, build it safely for the strip, build a street car, build it safely for the street, if you’re gonna build a street/strip car, then you gotta build it safe for both. Yes, you may give up a tenth or two on the strip, but if you and everyone gets to go home at the end of the day safely, that’s the important part.
I had to make this decision on my dart. It’s a road race build. I ultimately had to make the decision to not purse the fastest car and slow it down a bit if I wanted to safely transport my kids in it and cruise the country with it. Which meant, no roll cage. So I ditched the ideas of full fiberglass front clip and trunk, aluminum floors etc.
funny thing about Ackerman, I’ve seen guys that have trailer queen drag cars doing what you’re doing, they wonder why the sometimes get squirrelly on the track. They start looking and researching and realize that Ackerman could be the issue, the convert to something with better geometry, don’t change anything else and suddenly the squirrel, in predictable launches and landings go away and they pick up several tenths. So yes, bad enough Ackerman can slow you down even on the drag strip.
Decision is all yours. Well and the owner. I just pray everyone lives thru the aftermath of this decision.