Wow G you know everything about anything

I did a compression test, 1-2-3 all 170psi, number 4, 155psi, so that's not looking to good for the head gasket. The clatter sound seems to be coming from the number 4 cylinder also, with my trusty auto stethoscope I can tell it's worse on that side of the engine (drivers) but can't tell if it's in the pan (rod?) or somewhere else, the sound is unfortunately quite noticable. Hopefully she's getting a new car soon enough, now this thing has become my mission. Without sinking TOO much more dough into it (the car was given to this person free, so far we've got about $500 in it), I'd like to get it running as the thing is still giving me fits. The head gasket I can tackle, having a shop nearby to check/machine the head if needed. You referring to the timing chain g? I assume, the chain is kinda noisy, but no more so than the one on my friends 89 grandam, listening with the steth that is. I always thought if a chain goes your not in as much danger of a valve crashing or what have you as with a belt. Am I incorrect on that? And if I am, and I end up putting a head gasket in, I can do the chain at the same time. Thanks again for your time G.