Splined Sway Bar Info?

[ScotI]

I'm currently wrapping up a coil-over conversion for my '64 Chevy truck that has an assorted group of aftermarket parts that don't want to play well w/a traditional sway bar set-up. The mods consist of an aftermarket front cross-member (Porterbuilt) & narrowed a-arms (also PB). I have mocked-up multiple C10 bars as well as an f-body 1Le 36mm bar but only one lines up anywhere near close to the lower a-arm link mounts. My set-up = approx. 39.25"-39.375" wide @ the center of the outer link mounts on the arms. Others I've measured:

Belltech C10 'Sport' bar @ 1.375"od = 40.5"
Stock '00 S10 OE bar = ~41.5"
3rd GEN f-body 36mm bar = 43.75"
G-body Malibu OE bar = ~43.5"
Addco/Porterbuilt C10 bar = 44"

Of these units I played with, the Belltech bar is closest but still too wide. I can possibly get creative enough to get it to work @ the a-arm mounts but once you put the frame-pivot bushing housing on the bar & mount it to the bottom of the frame rails, it's the lowest hanging item on the truck & it's @ a very vulnerable spot. I have reached out to Porterbuilt to see if they have a narrower sway-bar that fits my dimensions but w/the mounting position @ the lowest portion of the frame being a concern, I sat back & wondered about alternative mounting of the bar. Moving the mounting location farther back w/the Belltech bar did help w/the mounting height (the frame starts to curve/rise in the area) but created other packaging issues. The shape of the bar is not ideal as-is which limits clearance as well so that's also a possible packaging issue (it may/may-not interfere w/my current minimal width front wheel/tire combo).

Ideally, I need to mount the bar within the frame rail vs. below it so I don't add a clearance concern to the bottom of the chassis which was purposely built to minimize clearance concerns.

This has me researching a Splined Sway bar as a solution. I've been doing basic Google searches for a few days & did find some info but where one source provides spec data, another doesn't (making it hard to determine what to get). Most I've found are race-car/rear set-ups. Welder Series has a DIY kit but it's not really a splined assembly nor do I feel it's adequately sized. Speedway has basically what I need (it's a 64-72 A-body spec kit) but it's too wide & they don't list narrower options in a similar configuration. I attached images of the Speedway/A-body set-up. A kit like this w/options for the main bar width is what I feel might work.

If you've been down this rabbit hole & know of a source/sources for splined sway (Torsion) bars, let me know.