Formula 1 teams run the under the 3 liter formula, with a compact stroke (42mm) and 95mm bore. *Jaguar Cosworth R2 Data*
The short stroke(and other factors) allow the engine to spin upwards of 18,000 rpm. You couldn't do that with a "stroker motor"

you would need a crank with a longer throw to get the piston down deeper in the cylinder wall to allow more air and fuel, increasing the overall displacement of the engine.
seems like it would be easier to just do the 3L swap IMO

98.5 SVT
93RX7
86GT 377ci