hey i dont have a bulb under my hood and wanted to know what size it is and if im going to adjust my timing how much should i do?

oh my bad guys its an 89 camaro rs

This is a example of why a signiture with some general info on your car helps. This a 305 or a 2.8 RS?

Shouldn't matter though .. anyways....normally its a 1156 bulb. Standard single filiment taillight/reverse light bulb.

for timing, a lot of TBI people run 5-6 degrees base advance. You can do that but if you hear pinging then back it down to 2-3 degrees. Remember to disconnect the EST wire.