How do i get rid of this governor on my 85 Riva??

[CuRbO]

my riva is super clean, 1500 miles for an 85. rides nice, but tops out at 35 and some sort of rev limiter or something wont let it go past 35mph. When i take it downhill and it wants to go faster than 35, something limits it.....how do i get rid of that so my riva can keep up with my riva jog (45mph)???

Instructions?

Negative side effects???

Will drilling holes in the exhaust help at all?