Their hired hit-man, Norman White, also received 18 years for his part in staging the car plunge to look like an accident.
All three were unanimously found guilty on two joint charges of attempting to murder Ivor Stokle, 34, Stroud's former common law husband, and his new girlfriend, Pauline Leyshon, 43, at Barrow Wake, near Cheltenham, Gloucestershire, in order to gain pounds 138,000 in insurance money.
The jury at Bristol Crown Court was told that Stroud and Evans saw a similar murder on television in a film called Fighting Mad two weeks earlier.
The judge, Mr Justice Swinton Thomas, said the couple were lured back to the bungalow at Staunton once shared by Mr Stokle and Stroud. There they were attacked by White, wielding a knife, while Stroud gloated to Mr Stokle: 'This will teach you to shit on me.'
The couple were taken to Barrow Wake, tied up and put in their car, which was set alight as Evans shouted 'Flame-ho'.
The judge detailed some of the injuries sustained by the victims. He said they still required painful operations, and the scars would remain for the rest of their lives. They are understood to be planning to marry.
Stroud, 32, a horse dealer, and Evans, 31, unemployed, both of Staunton, and White, 30, of Gloucester, had all pleaded not guilty.