In March, the 240 started firing on 3 cylinders, and my (and my mechanic's) initial theory was that the car had a snapped connecting rod. Well, today, I finally found the time to take the head off the engine, and I found out that one of the intake valve springs is broken. Otherwise, the pistons and bores look good as new, and there isn't even much carbon in the motor.

My questions are:
* Where can I get valve springs for the car without paying dealer prices or tearing into engines at a junkyard? FCP Groton doesn't list them on their site.
* Should I replace all of the valve springs, or just the one that broke? Should I replace the spring keepers and split collets as well?
* If the valve clearances are in spec now, will I need to reshim after replacing the springs?
* Can I reuse the head bolts, and what torque should I use when tightening them? Also, what torques should I use for the exhaust manifold, intake manifold, and camshaft cap bolts?
* Apart from the timing belt, head gasket, intake gasket, exhaust gaskets, and the heater hose that's buried behind the engine (and which I had to cut to remove), should I replace any other parts while the head is off?
* Am I better off using stock gaskets, or is the Elring stuff that FCP Groton sells ok? This is not a job that I want to do more than once.
* Should I bother cleaning off what little carbon deposits there are in the motor? What's the best method - wire brush + drill?

Thanks in advance,
-b.