An 1/8th buggy will hit 70mph no problem... Run a loose clutch and alot of gear, no problem as long as you've got enough radio range.. With off-road race gearing(13/14/15 tooth clutchbell) it won't.. But Kyosho used to make 17-21 tooth clutch bells, and with one of those it'd hit 70 MPH.. It'd be a dog on the bottom end, but it would get there on the top end.. I've had my 1/8th Mugen clocked at 55MPH with 14 tooth clutchbell and an RZ-BV99...