Salt thumped 119 off 57 balls as England tore into the West Indies attack to make 267-3 - surpassing their previous highest T20 total of 241 against New Zealand in 2019.
Ten sixes flew off Salt's bat as well as seven fours as he hit the highest total by an England men's batsman in T20, eclipsing the 116 by Alex Hales in 2014.
Captain Jos Buttler and Liam Livingstone joined the party with quickfire half-centuries.
Buttler's 55 came off 29 balls with his three sixes making him the English batsman with the most sixes in T20 internationals - 123 in total.
Salt also struck a belligerent 109 not out in the third match of the series to deny West Indies a 3-0 series lead and he proved unstoppable again.
"I am definitely enjoying it. It's a cool place to come and tour and play cricket," Salt said.
"The boys have produced the goods in the last few games and now we have the decider to look forward to."
The series is now locked at 2-2 with Thursday's climax to come.
In reply to England's huge total, West Indies lost opener Brandon King off the opening ball bowled by Moeen Ali but reacted in dazzling fashion with some sensational hitting to stay above the required run rate although wickets fell at regular intervals.
Nicholas Pooran hit 20 off the first over after King's dismissal and made 39 off 15 balls before falling to a brilliant running catch by Harry Brook off Sam Curran's bowling.
Sherfane Rutherford also blazed away in spectacular fashion as West Indies brought up the 100 in the seventh over but their chase was doomed to failure as wickets tumbled.
Rutherford fell lbw to Rehan Ahmed for 36 off 15 deliveries and from then on their chances of an unlikely victory faded.
Andre Russell made sure West Indies went down swinging as he clouted 51 in a desperate last stand but was eventually out to a steepling catch by Brook to give Topley a third wicket.
An incredible match contained 33 sixes and the fireworks could continue in the decider.
"The boys like a final it seems! We will come with brand new ideas and plans and see if we can entertain our fans at home," West Indies skipper Rovman Powell said.
"We have failed to close out the series from a good position but Thursday is an opportunity to do that."
