HELP!!!1977 dodge b100 sportsman van

[Jowseftayler]

Hey there, I just bought a fixer upper 1977 dodge van that I think is a sportsman b100. Anyhow the guy said that the mechanic told him the engine was only doing 20% compression in all the cylinders which meant it was a timing chain problem. So How do you know when you have it just right if theres no tick marks, and whether to go with a double roller or not on the timing chain. Thanks for your time!

[Dadof6]

First thing I would do is get yourself a service manual. There has got to be a mark of some kind on both the crank and cam gears. the manual should show how to identify them.
Always go with a double roller chain if it is available. They are made much better and will not stretch like a standard chain can.