I have a bucket seat original 4spd 72 demon and Im a tall guy. All the stock shifters I tried had the same problem as you- my knee hits them. Including bench seat sticks.

Along with long legs I was blessed with long knuckle dragging monkey arms. The solution for me was a short (comes about 6" out of the floor) shifter with a pistol grip for a little extra leverage. It does require a little extra oomph to shift but it's no big deal and the shifts are positive and short.

My bent knee is able to hang over the shifter for clearance and comfort and I don't have to lean foreward to reach it. A short or feeble guy might not have as much fun with it though.