68 dart 318 troubleshooting challenge

okay I got an optima battery, replaced the ground cable from battery to the block, and replaced cable from battery to the starter. now I get a consistent spark when I take out a spark plug and ground it on the exhaust manifold, so i think the spark is good now...

by reading around here on the forum, I am starting to wonder if I slipped a tooth on my timing chain? I have been cranking her over while turning the distributor back and forth to no avail.. I did think i heard a different noise when I was cranking it the first time it failed to start (different in a bad way) do timing chains slip while you are cranking the engine over... or do they ususally only slip at higher rpms?

would putting #1 piston at TDC and checking to see that both valves are closed be the right way to rule out the timing chain?

any help appreciated, this car is wrecking my self esteem...