sr timing chain rattle

[statik]

I've searched around a bit and I believe im suffering from the infamous timing chain rattle on my SR. I just recently pushed 300whp+, more specifically i just installed an underdrive pulley a few days ago when the problem started. After the car is warmed up and running you will start to hear a clicking/rattle noise coming from the front valve cover, then slowly u will start to hear the ball in tin can noise. if you rev the motor, at about 3k-3600 the rattle in the front valve cover is LOUD. Sounds almost like an exhaust heat shield is rattling, only coming from the front valve cover(no i dont have any exhaust heat shields to rattle).

If i turn off the car for say, 5 min, when i start the car again, no noises, after about 1-2min the noises come back. Could this just be the upper chain guide? Courtesy parts has them for about $13, but im pretty sure I can run it without it. Im guessing the tensioner would need replacing too...

Anyway i plan on pulling the valve cover this weekend, wish me luck? i dunno, if anyone has had similar problems with there SR, advice would be welcome