The game stands to be a crunch encounter in the National League South title race with both sides sat at the top, tied on points.
The Gulls have been in fine form all season and have packed grounds wherever they've been - as well as drawing average crowds of over 2,000 at Plainmoor.
Johnson hopes the players and staff can repay their support with the top prize.
"There was never any doubt that we'd sell out, but to do it that quickly is fantastic," he said in an interview with Devon Live.
"There's a real nice affinity between the management and the players and the supporters at the club now, and it's genuine - we are not making it up.
"If nothing else, our supporters, especially the ones who travel, deserve a promotion, and we are trying to do everything we can to give it to them."
With nine games to go, it looks to be a two horse race for the title.
Torquay travel to the Kingfield Stadium on Saturday April 4 to face Alan Dowson's Woking.