computer & timing

[Smokin86]

been workin on the truck a lot lately. it would crank all day, but never start. we got it finally figured out, but i got some questions.

this is what i did

the module and pickup were bad so I stabbed a rebuilt distributor in it. still wouldn't do anything. bypassed the computer under the dash by connecting a & c on the plug. it starts and idles now pretty good.

now the questions

what should i set my timing to? i adjusted the timing until it idled even enough by sound so I could drive it home from where it was dead at. Now i want to set it correctly with a timing light. everything is stock on the 305.

what does the computer actually do? my mechanic told me to bypass it. it worked, so i went with it. What are the consequences of bypassing it? what else is part of the system? any info about it would be appreciated.