Rodney,
We ran a Sanger, a Hondo and a Hallett, all flatbottoms. The Sanger was really a ski boat, it only turned 82mph in the 1/4, the Hallet would run about 95 since it was lighter and had more motor. The Hondo was a runner bottom potatoe chip with a blown/injected 468 BB. The best pass on that boat was 138mph (open cockpit, early 90's), eventually that boat went over killing the driver and ending my interest in boat racing.
One done one to go... It's hard to see in the pix but the RM header is about 2" taller and 2" wider.