Hello All

I just bought a 1986 G20 carbureted 5.7L Van. My first Chevy. I know shes old but its in great shape and 147,000 KM's !! Its got a heavy duty emission exhaust and i believe 3/4 ton chassis. I am looking for any shop manuals or service manuals for this van. It needs engine work as it wont start. I believe the timing is out of whack and may have jumped a tooth. So i have a series of questions:
1) Any advice on replacing the timing gears and chain
2)I want this motor to run sweet so what else should i do to it to get the best running results. I am looking for a reliable somewhat fuel efficient engine. Any upgrades to consider?

thanks in advance for any advice