Got to love the F-H series motors for being interchangable... Like Emino said make sure u get a better clutch too, and I know my buddy put an F23 trans to his H22 and it didn't like shifting past 7K, idk if it was just that trans or because they weren't made to do it... So if u plan on racing it, I would consider an H22 trans..(PS: his blew up 3 months later in a race too)... And also have u considered just the H22, cause the F20 if I remember correctly doesn't have as much torque, but the same Horsepower as the H22 for the same price, usually???