It looks like I need to replace my harmonic balancer.  The rubber ring is protruding quite a bit in one spot and it's at least close to rubbing on the timing chain cover. 

Funny how this all works, huh... BTDT !

I repalced mine without taking the water pump off. I removed the fan and pulley. There was lots of room to get the puller/installer in there because of the angle the radiator is at. I also replaced the seal. That being said, it sounds to me like you have the "while-I'm-at-it" thing going. Time to pull the motor and do it all.

The balancer can be changed with the water pump installed. The timing set cannot, tho.
You can sneak the timing cover off the front without dropping the pan, but it's a major pain, and you stand a big chance of a leak if you haven't done it many times, and know the subtle tricks of getting it back on. Dropping the pan on a Corvette is waaaay easier than doing the timing cover twice(or more) because it leaked.
So...I'd say drop the pan, replace the timing gears/chain(with a true roller design), maybe think about replacing the oil pump with a high volume pump, install a new balancer, and be done with it.
I wouldn't toy with the rear main seal at this point unless it is already leaking...

Thanks for the advice, guys.  I'm glad I found out that I can do the balancer without taking the water pump off.  I may do only that for now, but if I get ambitious over the winter I'll drop the pan and replace the timing gear and oil pump like Joel suggests.  The rear main seal does leak a bit (don't they all ), but it's not a bad leak so I can probably get away with it for awhile.

I am going to be doing the harmonic balancer thing to my 81 this summer.  Got 124,000 miles on her now.  If it ain't broke, no need to fix it, I say.

It is possible to replace the cam in the car, but it is probably as much extra work as just pulling the engine and being able to get at everything and replace all the gaskets and rear main seal.  And if you replace the cam, you either need to go with a low RPM torque cam or replace the heads to increase air flow.  In which case maybe you should replace the pistons to raise the compression, then maybe.......

Larry

That ,you may as well ,as long as you are there,list can get quite extensive and expensive Ron 782009-11-17 17:27:03

  Yes Sir REE,  I agree. Start at the radiator and end at the clutch. Do it ONE (1) time and DONE.  It may seem extensive but you will not have to deal with it again.  Just look at all the time you can spend driving and enjoying and NOT be concerned with "Whats going to happen NEXT"

[QUOTE=daveo76]The rear main seal does leak a bit (don't they all ), but it's not a bad leak so I can probably get away with it for awhile. [/QUOTE]

What you think is a rear main leak may well be the oil pan leaking....which can be corrected while you have the pan off doing the other stuff. The rear main can be changed in the car, but it involves loosening all of the main cap bolts, and letting the crank drop down a bit. That gives a little more clearance to sneak the seal out from the top saddle, as well as the clearance needed to re-install the new seal without buggering it up...which will make it leak...still...

I wouldn't fool with a cam swap on a stock L-48...the results aren't worth the effort. The cam can be swapped with the engine in the car, but you'll have to remove the radiator, and dang-near remove the A/C condenser, and well as the intake manifold. Removing the hood is better, too.