Andreas, I think you need to think about the look from your new engine. Should it look stock and should it be a "better" original motor or something special modern?
For the 3.77 gear , I would go with a stroker 393 kit . You can use your 4V heads , but they are a lot of work to make them going. Mill the pedestals and some port work is in my opinion the way to go. Stay at about 10.7 : 1 compression rate because of the thin block walls .
TM makes nice stroker kits , also I love the nice pistions from him. He done a internal balanced kit for me and it was realy nice.
When you stay under 6500 rpm a restricor set for the oil is enough.
Better is to bush the lifter holes.
Where are you located ?