I would not use alum for what you are doing, I would go steel or chromoly.
In my opinion a 3.5" steel shaft would be overkill with 1350 solid U-joints. Since you are shipping it to Sweden the shipping costs will exceed the driveshaft costs so get the best one you can get. There are templates explaining how they measure on their website.
I would recommend Mark Williams if you don't have someone local to you that is capable. I use a local shop and they use the same materials and process that a Dennys would be for considerably less cost and I can get one in the same day.
3-1/2" Heat Treated Chromoly Drive Shaft
The 3-1/2" in Chromoly driveshaft offers a 19% higher critical speed and a 22% increase in torsional strength. Comes with Heavy Duty Impact Joints and dynamically balanced. (Transmission yoke not included.) Check service bulletin # 0049 for operating limits and critical speed charts.
B - What 1350 series pinion yoke will be used? :
E - Trans. seal to rear U-joint centerline:
F - Amount of output shaft past trans. seal:
New M/W transmission yoke: 39005 Powerglide/T-350 (add $182.00)39013 Lenco 32 spline (add $182.00)39022 C-4 ford (add $182.00)39040 G-Force 16 spline (add $182.00)39035 hardened powerglide yoke (add $197.00)Select yoke39004 T-400 (add $182.00)39002 Mopar/Doug Nash/Liberty (add $182.00)39015 Lenco 16 spline (add $182.00)39020 C-6 Ford (add $182.00)39034 hardened Jerico yoke (add $197.00)39032 hardened Liberty yoke (add $197.00)