Various Issues with 03 cobra

It's a buddies 03 he is having several issues with it.
1. It goes through coolant at a rapid rate. After burping system then driving it over flows the overflow and then coolant comes out seemingly everywhere.
2. It has now developed a loud TICK. Sound like an extremely loud lifter tick form and older pushrod engine or a rod hitting the oil pan sound. However it goes away once the engine is at operating temp, it increases with rpm, and it is doesn't do it if the coolant system is full. I went over to listen to it and the noise seemed to emit more from the center of the car, but as I'm sure everyone with a mod motor knows they can throw you off with that deep valley.

He bought the car bone stock with 15k miles on it. He has added midpipe, catback, and then a few weeks ago a smaller pulley, and mailorder tune. Car has had the coolant issue since about october but the noise just started this week. He pulled the oil filter yesterday and cut it open it looked fine no metal in it, changed the plugs they all had a nice light brown color to them, the car still drives well, and pulls strong, but he doesn't want to drive it and damage something.

Well blown headgasket was kinda what I was thinking myself, even though you hardly ever hear of one. The cooling issue started before the pulley swap, actaully the cooling issue happened after the car had sat for 2 months awaiting the t56 rebuild.
Yes he has burped the system properly. Was also why I was thinking headgasket.
Plugs he swapped in ngk tr6's gapped at .035. Tune is from Mile High, which to his understanding is a very safe reliable tune.
As for oil and filter - Mobil 1 synth, with a mobil 1 filter. Noise started before oil and filter change.
The tick/ knock started about a week to 10 days after the pulley swap and the tune was flashed when the pulley was installed. It does have the ticking injectors, I know that sound and could hear it separtely. I was crawling all over the top end and under what I could of the car while it was running. I too thought exhaust leak but he double checked the xpipe and it was tight. I ran my hands as close as I could and felt no leak.
As everyone know with that valley a noise is hard to pinpoint.

here is the things I was thinking.
exhaust leak - too loud for it though and couldn't feel a leak.
blown headgasket - but no coolant in the oil, no smoke once warmed up plugs sligthly brown in color ( in my experience blown head gaskets give you a very white plug)
broken wrist pin - Although I would think the noise would always be there, right? also performance hasn't fallen off.
bent blower shaft - Once again I would assume a more grinding sound, and for it to always be there.
Loose /broken rocker - Once again I would assume it to always be there and lose of power.
dented oil pan - But no shaving in the oil.
Too much oil draining out of head - but the noise stays until it's at operating temp usually oil would already be there. Right?
As for the head tick - I've heard some with the dreaded head tick the ones I've heard were slightly louder than an injector tick about like an exhaust leak and his noise is REALLY loud.
He did run a compression test after the cooling issue started and he told me they were all the same. He didn't remember the psi though.

Thanks Uncle Meat thought I was going crazy. I'll ask him if he did any highspeed runs.
Yeah he changed the oil yesterday and cut open the filter because we had been worrying about bottomend issue. The oil was fine was nice and clean. I checked the dip stick and it was only oil on it.
That's what's driving me crazy everytime I think I got an idea it gets canceled out.
I'll see if he can run a leak down test on it.

Talked to him no prolonged highspeed pulls since pulley swap. All he has done is some 1-3rd pulls.
Pulled the radatior and took it to a shop accordign to them it was clogged.
Some have suggested the flywheel has broken. I've never been around a broken flywheel and the car still able to move under it's own power. The ones I've seen your usually lucky if you keep your legs.

U.M. Yeah I suggest he do a leak down and another compression test. But I'm an idiot so......
Your thinking on the flywheel is the same as mine in that it would always be there.