[Vpmedia]

its easy

you need to edit following files

A-20's:
motor.PrattWhitney_R-2600_Series.prs
F4F's, SBD's
motor.PrattWhitney_R-1830_Series.prs
F4U's, F6F's
motor.PrattWhitney_R-2800_Series.prs

look for [spl] and increase the numeric value