I can't speak for a 170, but I've done 105 on level ground in my 225/904/2.76 Dart. It's stock aside from a 390 Holley. Top speed with a passenger was 98, also on level ground. Given that, plus the 170's lower power but willingness to rev, I'd say 90 is feasible.
Have you ever watched Duel, a 1971 Spielberg movie starring Dennis Weaver? Anyway, he drives a brand new 1971 Valiant in the film. If nothing else, it taught me that getting chased by a demonic oil tank driver can far exceed factory top end specs.