Before you tear them down run a compression test on both. That will tell you upfront of where the problem cyl(s) are as well as overall condition.
Before you run the test. squirt some oil in each cyl and let it sit for a couple days. Then fill up the oil to the proper level, use el-cheapo oil, then remove the dist and cut off the tang on an old used long straight slot screw drive and use your dill to turn the oil pump clockwise to see if it will pump up some pressure. A good sign would be that oil starts seeping out of the rocker arms weep holes. Once you've got oil circulated then run reinstall the dist and run the compression tests.
If the tests come back fairly good I'd recommend to try and start it(them) up before teardown.
Good luck
Dave
