Opener Grace Harris (54 off 33 balls), Charli Knott (32no off 14), Amelia Kerr (31 off 23) and Laura Harris (24 off 11) all posted handy scores in the Heat's massive total on Wednesday night.
If the Scorchers are able to secure victory it would mark the highest ever successful run chase in WBBL history.
The biggest successful run chase was in 2019 when the Melbourne Renegades posted 4-185 in reply to the Heat's 4-183.
The winner of Wednesday's match will face the ladder-leading Adelaide Strikers in Saturday's grand final at Adelaide Oval.
The Scorchers' bowlers struggled against the Heat and the home side was also sloppy in the field at times.
Amy Edgar dropped a skied sitter off her own bowling when Kerr was on 30, while Piepa Cleary stepped over the rope after taking a catch when Mignon du Preez was on 20.
The errors only cost a total of seven runs but the powerful Heat batting line-up was able to feast on the Scorchers' bowling attack throughout.
Scorchers star Sophie Devine copped the most pain with figures of 0-41 from her three overs while Edgar (0-35 off three) and Chloe Ainsworth (0-25 off two) were also pummeled.
Spinner Alana King (3-30 off four overs) was the most dangerous and economical bowler.
Grace Harris got the party started with 10 fours and a six, with her half-century coming off just 26 balls.
The Challenger is on! — Weber Women's Big Bash League (@WBBL) And Grace Harris finds the rope with the second ball of the evening. Strap in #WBBL09 pic.twitter.com/fZJZh5zVJ6November 29, 2023
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