Alcoa window balances

A home owner from USA says:
Hello,

My 1979 house has Alcoa aluminum windows that do not tilt, they just go up and down (but only the bottom half). I'd like to replace all of the balance spring sets (plus the handles, locks, gasket and the little stopper tabs at the top!), but I don't have a clue of what the part numbers would be. If possible, I'd like to get identical premade units rather than having to put them together myself.

I've attached three collage photos to show you the channel, top plastic piece and bottom plastic piece from various angles. The measurements are as follows:

Channel: 25" x 5/8" x 5/8", with "2430" stamped on it

Top piece: 1 3/4" long (including tabs at end set into channel), just under 5/8" wide and 3/4" deep

Bottom piece: 1 1/8" long (or more - I can't see the end because it's under the little pulleys), 5/8" wide and 1 1/4" deep

Please take a look and let me know what I need. Thank you so much in advance!
User submitted photos of a window balance.
Profile picture of Tom
Tom from SWISCO responded:
Thank you for reaching out to us. Please take a look at our S350-25 channel balance with a 2430 option. This may be what you are looking for. Get back to us and let us know if you agree.
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