Well I just changed the plugs on my chevelle, and noticed that two plugs (3 & 4) were very carbon deposited. The other plugs were slightly oily, but not enough to foul them completely. I've occasionally had white smoke (not coolant, takes too long to dissipate.) at startup and idle immediately after startup. These only seem to happen after the car has sat up for a few days. I'm thinking that this could be caused by leaking valve stem seals, but am unsure if there is anything else that might be causing it. I'm planning on changing them out in the next week or so, whenever I have some time. I also pulled the plugs the next day after changing them, and noticed they too were oily/carbony. My motor ran rich for a long time before I retuned the carb as well. I'm wondering if this caused alot of carbon build up in the cylinders and cleaning them with something like seafoam would be good. I'm already planning on flushing the radiator today, so seafoaming the motor wouldn't be much more to do.

I'm not 100% sure its valve stem seals, but I imagine its highly likely that's what it is. I'm up for anything I can try, anything else it might be, or any reason that I might be wrong. Also should I try to use the seafoam to clean out the current cylinders, then clean the new sparkplugs to try to help the motor run as well as possible for as long as possible till I can replace the valvestems?

EDIT: If any pictures would help, I'll be glad to take and post them.

EDIT 2: After researching, and talking to a buddy of mine, it is probably just running way too rich at part throttle, and fouling the plugs. I'm going to retune the jets and see what I can get it to do. Probably replace the valve stem seals while I'm at it. I plan on doing what it takes to get the motor running right.