Stuck in 1st gear

my brothers duster did that, fresh rebuilt engine, trans, and shifter, every time i rev it up in 1st gear and tried to shift in 2nd it would lock up tried for two day ujusting the shifter no luck purchase a new hurst shifter perfect been 3 years no problem, when i laid under the car watching my brother shift from 1st to 2nd i could see the reverse lever move and that caused the lock up, dis connect the reverse rod and move the lever to neutral should free it up good luck with it.