Paul,

<<Oscar's O-320 was a totally-stock -B model converted to dynafocal engine mounts.>>

 <<would go 242 mph TAS at 1000' dalt at 3200 rpm>>

 

What are you assuming for power output at these high engine speeds?  Simply extending the torque curve for the example at 3200 rpm puts power at about 185 hp @ SL.(178 hp @1,000')  Since this data is not readily available above 2,700 rpm, it would help if you could include these numbers along with the final TASs.

Chris