Are any of the aftermarket upper control arms worth it for a street cruiser?

I have a 67' Belvedere II with a built 440. Other then upgraded sway bars front and rear and a Borgeson steering box the steering/suspension is stock. Is there much value for me in upgrading the control arms? The reason I am contemplating it is when on the highway I notice that the car gets pulled into the ruts easily and I thought more caster might help with this.

Did you read the post right below yours?

hope you aren't running bias plies

^^^ Yup - 1st question: bias ply tires ? They'll follow any ruts or uneven surface.
Night & day difference swapping bias to radial with no other changes.
As for the aftermarket upper arms, I haven't found them necessary for my street cars using radial tires.
Generally, more caster will be better to drive straight, and I try to get about 5 degrees with the stock stuff if possible.
FWIW, my drag car had Jack Arnew's altered OEM upper arms (widened), and about 7 degrees caster, and it went straight as a string even on bias plies.
The steering wheel would unwind with a vengeance after turn-outs, but no biggie vs stability @ 130 or so.
That said, it was never street driven, and track vs street surfaces differ.

Radial tires. Nothing Fancy just some 15" M/T street tires I think they are actually a Cooper Cobra.

With the vinyl bench seat I'm not looking to corner carve. How much caster can you generally achieve with a stock set-up? When I bought the car it had manual steering and I swapped over to the power borgeson set-up so I imagine the alignment was set up for negative caster

The max amount available "stock" might vary a bit by car, but seems around 3 deg positive can be obtained.
Check out "Moog problem solver".
In any case, sounds like you need a good old-school alignment guy.

I have the name of a local shop most of the old car guys go to so I will chat them up soon.

For my use are the moog problem solvers worth the effort?

On mine I found, that when I used the offset control arm bushings it pushed out the upper part of the tire giving undesirable camber so I had to shim out the lower balljoint along with the offset upper bushings to get things where I wanted them.

But yes all worth it.