After adjusting my shift linkage the best I could, I found the shift lever still rubbed in the slots of the gate. So I got out the tool & die grinder and widened the slots where needed, until I could row the gears without the shift level touching the gate. The result was the car shifts very easily now.
As a reminder, the first step in making the shift mechanism operate easier is to remove the spring loaded detent built into the shift lever assembly. The transmission also has a detent mechanism, the one built into the shift lever assembly is redundant and only adds to the effort requied to row the lever.
One long time Pantera enthusiast has mentioned to me that removal of the gate can lead to the owner putting side loads on the gears while shifting, instead of moving the lever perfectly forwards & backwards. Something to ponder.
cowboy from hell