Any benefit to a tubular K-frame that retains T-bars ?

[ardentind]

I have the K-member out of my '67 Belvedere. Its been blasted and I had planned to seam weld it and reinforce it.
Its ugly, ridiculously heavy, etc. I'd like to keep the torsion bar setup but keep thinking of how easy it may be to replicate the factory K-member in a tubular style, but that retains factory steering box mount, idler arm mount, and torsion bar mounts.

Less weight, a lot more room up front...any other benefits that anyone could see? I've yet to have a motor in this car so I cant really judge how tight things are in certain situations.

I know plenty of people will argue its not worth it, "Why?", etc...which is why I am asking. I have extensive fabrication experience and equipment. Laser cutting, press brake, Seigmund weld fixturing table, etc...the fabrication is not an issue. Just looking for input to help me decide whether I want to go down this road or just weld up the factory one, powder coat it and put it back in the car.

Thanks in advance.

 

[Kern Dog]

They are not ridiculously heavy.

They are far more rigid than any tubular K member. Your front end will be stiffer with a factory unit.

 

[WileE]

One issue I would see is ensuring the suspension/steering parts are correctly located for proper alignment. Another is the strength of the structure itself to withstand the weight and loads applied to it.

 

[eldubb440]

lots of work to save what, 10-15 pounds maybe?.......a K frame isn't all that heavy

 

[Jerry Hall]

Sure, it's heavy and sometimes poorly welded, but they are strong. I'm sure you could take a lot of weight off by doing this, but how strong will it be. Application, drag cars is what I see. Others would be for special engine applications like Gen III Hemi's or other setups. I like torsion bar suspensions, but have never thought of why one would try to redesign it. Most of the aftermarket suspensions i have seen just don't look strong. This is coming from a person that had a aftermarket Mustang II suspension almost kill him in a 32 Ford street rod. Chrysler had strong designs. I say clean it up, eliminate funky welds, paint and use it.

 

[WileE]

While thinking of your endeavor, consider weight of a complete engine along with gearbox, lift forces, lateral forces, as well as the geometric design for steering and suspension, engine mount orientation for proper driveline alignment, along with tensile strength of metal utilized in the construction. Oh... and don't forget that oil pan that might get in the way. On the other hand, the factory engineered proven part...

 

[66 Sat]

If you're attaching an engine that weighs 600 lbs and the most you can realistically save is 22 lbs (that's if you could halve the weight of the factory unit) with an unproven design of unknown strength and durability, then as said above - why bother?

But - you said you have extensive skills and the equipment, so if you actually enjoy doing this sort of thing then why not? Have a crack and show us what you come up with. If it works, then others may adopt your design. If it doesn't, then so be it, at least you tried. Plenty of times I've tried to improve something, wasted hours doing it and then chucked it away when it didn't work, but I had fun trying. Innovation, I love it.

 

[Kern Dog]

Plenty of times I've tried to improve something, wasted hours doing it and then chucked it away when it didn't work, but I had fun trying. Innovation, I love it.

Same here. I love to paint outside the lines and do some things different than what is OEM. I see nothing wrong with trying new things.
If one could build a tubular K member with some manner of reinforcement that actually ties the frame rails together....while resisting the tendency for the front structure from parallelogramming, it would be interesting.
Think of how a wood framed wall is built. A series of studs are attached at the top and bottom. It is excellent in compression but is not good at resisting torsional resistance until plywood sheathing is applied and nailed....At that point, the wall is super rigid.
The factory K member resists torsional shifts because it is rigid. The sheet metal used in it acts like the plywood on a wall frame.
You could duplicate that in some manner with a tubular K member but you're blazing your own trail on this since nobody else that I have seen has done it.

 

[dvw]

The K frame in my car has been heavily tested. 1250 runs over 13 years with wheelies every pass. The flanges were trimmed and tack welded as is was cut. A hole saw was used to make a nice radius for the oil pan cut out. Two oversized inserts were tacked into the oil pan cut out. Then trimmed for a flush fit. The motor mounts were removed. Leaving only the flat mounting area for the steering box. The box mounting plate was gusseted with two pieces of .090" moly tubing. The lower openings were filled with sheet metal for appearance. The steering shaft and strut rods were fabbed out of the same .090" moly tube for additinal weight savings. I wouldn't sugest these mods for a road race car but for a drag car they've worked very well.
Doug

 

[dsd1967]

Other than cleaning up the welds and stiffening the steering box area. The only other things I would consider is reinforcing the strut rod holes and replacing the press fit pitman arm attachment flange with a 68-70 u shaped yoke style attachment. Much less flex and better pitman arm availability if you want to use the longer pitman arm for faster ratio steering.

 

[493 Mike]

I went the easy way with my 66 wagon and cut a series of holes across the front vertical section. Not much weight reduction but, I thought it looked cool! Every ounce counts.
Mike

 

[Vertex_Jeff]

I have a QA1 Tubular K member in my '67 Barracuda that I drag race. I like it because it leaves plenty of room to install and remove my engine diaper. there is also a lot of room to drop the oil pan if needed. Weight savings was not a selling point for me. Just easier access and serviceability.

 

[threewood]

The K frame in my car has been heavily tested. 1250 runs over 13 years with wheelies every pass. The flanges were trimmed and tack welded as is was cut. A hole saw was used to make a nice radius for the oil pan cut out. Two oversized inserts were tacked into the oil pan cut out. Then trimmed for a flush fit. The motor mounts were removed. Leaving only the flat mounting area for the steering box. The box mounting plate was gusseted with two pieces of .090" moly tubing. The lower openings were filled with sheet metal for appearance. The steering shaft and strut rods were fabbed out of the same .090" moly tube for additinal weight savings. I wouldn't sugest these mods for a road race car but for a drag car they've worked very well.
Doug

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Wow! I like that a lot.

 

[ckessel]

Other than cleaning up the welds and stiffening the steering box area. The only other things I would consider is reinforcing the strut rod holes and replacing the press fit pitman arm attachment flange with a 68-70 u shaped yoke style attachment. Much less flex and better pitman arm availability if you want to use the longer pitman arm for faster ratio steering.

You mean, Idler arm?

 

[ckessel]

For my 65, I'm using a 70 unit. 3 reasons why I chose that over the 65 one are: double shear mount idler arm[ also easier to source for replacement] as its stronger than the bayonet bolt unit, pass through the frame sway bar mounting, moves the engine back 1.5". I did extensive welding, reinforcing on it. The usual areas like for the lower control arm shaft but even more extensive, steering box mount. I also boxed in the strut rod mount area. On the perimeter spot welds, there were around 30 from the factory. I added 120+ to that. Some of those are in the idler arm mount area. Lots of hole cutting with my Blair Rota Broach cutters. Pieces of metal I have in my stash plus my Lincoln Mig unit. Very little cash outlay, buts lots of time. As Greg and others who are into construction point out about shear walls and nailing patterns for such, my added welding was essentially making a stiffer unit like more nails in the shear wall.
On the tubular ones which are popular, some years back I went by the QA1 booth, while attending the SEMA show, to ask them about their's. I asked the rep a basic Mopar question. What happens when you put a floor jack under the unit to lift the front of the car? He had to ponder that a bit. Then he said, as long as you bridge across both tubes you should be ok. Should be ok is not an answer I wanted to hear.
This may come across as not embracing the current selections available. I'm not. The new stuff may be lighter, but at what cost? What's the gain/benefits compared to the cost/longevity/parts replacement? The oe stuff puts up with massive amounts of abuse on a daily basis. Bad roads, smacking potholes/curbs/Dukes of Hazard etc over 50+ years of use. I personally have not seen any feedback of said questions/concerns over extended, non trailer/non driven time due to season conditions[ ice, snow etc]. As an example of current offerings, although more high end, the units from Heidts look well done. Have seen their units at SEMA. Once you factor in units like these, plus the likely add on for the rear and you haven't done anything in the middle of the car, you're in the realm of just putting in a full frame from Roadster Shop/ Schwartz/ Art Morrison. One common complaint about one the popular tube offerings is that you turning radius increases.

SEMA 2025: Heidts Pro-G IRS, IFS For Mopar E-Bodies