Yep, figgered that was what you would find. Campbell Enterprises often is lower than Summit and Jegs on KB's. But that is still are a LOT pricier than the 526AP's, and the lighter KB's means re-balance....although that would be cheaper to do that since it will require taking weight off of the crank, not adding it on. That is why I keep poking all that info at you about drilling out pins and such....so you can bypass the re-balance cost.
You are good with working on parts so there IS a way to get the re-balance cost waaaay down: you do the rods and pistons yourself, and compute the bobweight and hand that bobweight to the shop to just balance the crank to your bobweight. (I'd be happy to explain how that works.)
I would not be scared to use the '83 cast crank.... all I can find is that they are good for 400 HP or more and you won't be anywhere near there with the lower port flow of the 302's, even if you put in the larger valves.