[mr0077]

Okay, if it is the arms...the arms on the side of the transmission would need to be shorter to get more radial travel, or the arms on the bottom of the shifter itself would need to be longer. I would think it would be easy to either make a shorter arm to bolt to the transmission or drill another hole...the only one you would really NEED to change would be the 2-4 arm, but then you would have a longer throw to first and third, with a shorter throw to second or fourth. I had a '68 Corvette (L-89) that had two holes in the shifter arms, inner holes for longer throws and outer holes for shorter throws.
From your description, it is not the shift ROD length, as you adjusted them with both the shifter and transmission in neutral...