Me thinks your goal of running in the 8 with a 383 in your car are unobtainable
All kidding aside, that car is heavy and those motors are limited on how much cheap power you can make with them, been there done that(multiple times)
Can you find a usable 440 crankshaft? If so I would use it by turning down the mains to 383 size and have a set of pistons made for using the stock 440 rods in your 383 , you will have to do some work, grinding the edges, on the crankshaft counterweights to clear the main webbing but increasing the stroke to 3.750 in a low deck is a really good way to help on the low end torque.
Being in Sweden has to limit your ability and choices on parts for this project so I can feel your pain and frustrations good luck