To do it properly you will need a timing light. Attach it to the number one cylinder spark plug wire and start the engine. Hold the light so you can see the harmonic balancer and check where the timing mark is when the light shines on it. If you need to adjust it you will have to loosen the distributor hold down bolt about 3/4 of a turn. Rotate the distributor very gently until the mark lines up with about six degrees advanced and your 305 should run fine. remember to tighten the distributor bolt back down.
6 BTDC
Computer controlled and not adjustable
On the front of the timing chain cover, drivers side towards the top of the harmonic balancer.
To adjust the timing on a 1992 Chevy 305, first ensure the engine is at operating temperature. Locate the timing mark on the harmonic balancer and the timing tab on the engine block. Use a timing light to check the current timing by connecting the light to the number one spark plug wire and pointing it at the timing mark. To adjust, loosen the distributor hold-down bolt and rotate the distributor slightly until you reach the desired timing, then retighten the bolt.
6 or 8 drgee
There is no timing belt on a 305 unless it is an aftermarket belt drive system.
yes
Top Dead Center
6 degrees BTC
same as a 350
The easiest way is to look at the Harmonic Balancer. The 305 has a wider thicker balancer than the 350. Pus the timing tab on a 305 is located ON the timing cover and the 350 is bolted on the with the cover bolts. Riky9
There is no information on the internet about what the special feature of the Chevy 305 engine is, in fact, the Chevy 305 and 350 are interchangeable, one is just an older model.