If the column linkage isnt adjusted correctly, the trans wont go completely into 3rd. Make sure the shift arms are correct on the splined shift forks shaft, the shift rods are adjusted properly, and the shifter box and shift bushings on column aren't worn out.

and thats no bull shift wink

Preaching the Hot Rod Gospel according to the 4-stroke apostles:

Suck, Squish, Fire and Fumes