Tim,
Both the Hurst and the factory shifter are adjusted similarly.
The shifter itself has not detents for the gears...
On the Hurst shifter, you remove all three rods from the shifter (1-2, 3-4 and Rev). Then you place all three shift levers on the shifter body in neutral. There is a small hole that you insert a 1/4" (approx) alignment pin (drill bit or allen wrench will work too) that is inserted through the shifter body, all thre arms and through the other side of the shifter body. This will hold the shifter in nuetral...
Then with the transmission in neutral (all three levers have detents inside the transmission that hold them in gear or in nuetral)you can adjust the rod-ends/swivels on the shifter-end of the rods (one at a time)until they perfectly slide into the arms on the shifter body... Then you remove the alignment pin... The shifter should work very well now (old one may still feel loose due to wear)...
The factory shifter is similar, except the alignment pin is a flat piece of stock... I forget the dimensions, but its in the assembly manual (about 1/2 inch wide?).
There is also a secondary adjustment that has to do with the stop-bolts.
These are what keep your from shifting too far and wrecking something. This keeps you from shifting too far... I am not sure on the actual procedure, but I shift back into second making sure it engages completely (car not running) and then adjust the front stop-bolt until it just hits the internal shift lever (after a while, you can feel when it hits...
I do the same with the rear bolt by shifting into 3rd... You should probably check 4th, but I am usually worried about 2nd and 3rd, because thats where I am going to be really banging gears...
I think Hurst web site (Mr Gasket Company) has down-loadable instruction sheets... Probably with diagrams, etc...
If you want to keep it stock looking, you can built a simple bracket (welding required) to bolt the factory Chevelle handle to the Hurst shifter body. Then it will look stock but have the better shifting of the Hurst... If you want reverse-lights, hurst sells a separate switch assembly...