The guys in my club, the Middlesex Modelers, have been working on their vintage combat models for the past few years. One of the guys had that same engine on a Half Fast and was doing 105 MPH.
I was also using my 1967 style 36X BB on this larger combat model that I picked up on EBay a few years ago,
it was clocked at 111 MPH.
Larry Scarinzi was there flying with us, it was on one of those nice warm January Sundays we are having here in NJ this year.