The removal of the belly scoop.
Odom used wing tip radiators and Leeward used total loss steam cooling.
But it's the belly scoop that makes me interested.
This from The Skyracers "Speed Kings of Aviation's Golden Age" Joseph Hood 1969.
"the removal of the radiator and scoop caused a tendency to pitch up in an uncontrollable
manner.
An number of solutions were tried the best was found to be a bob weight added to the control stick
that dampened the movement in high G turns"
Odom also had aileron problems due to the cropped wings and tip radiators.
Food for thought?
HH