Ok, so let me suggest that you try the best and cheapest solution first for physically returning to 1981.
I don't know your location but I assume you can find a ley line, or better yet, a ley line intersection near you (I would use a pendulum to assist in defining a GPS coordinate before you leave the house). Go to that location and build yourself a rotating torsion machine large enough for you to fit yourself comfortably into. This would be basically a rotating spiral wall of metal (aluminum sheeting recommended) on a metal platform driven by a variable speed motor. The control variables are going to be rpm and that the time travel must be executed during a spiral alignment of the inner planets. Specifically, the 5 points making up the spiral being Sun-Mercury-Venus-Earth-Mars. This alignment creates an aether tide for increased gravitation effects. You might notice with an orrery that this spiral alignment condition created the gravity effects that fueled the most powerful hurricanes in the US. Hurricanes also display time and gravity effects like depicted in the book, The Philadelphia Experiment. You should also be aware that time and gravity are linked so a change in one is going to cause a change in the other.
This is probably the easiest method to employ to get there and then. What part of the world are you located, Ejie?
