87 chevy 350 rough idle?

valve stem seals are bad for sure and does'nt want to stay running at idle. runs smooth top end and not a noticeable power lose. can valve seal problems be causing the miss. changed all ign. components, still acts the same.

I would say it is time for a valve job, you may want to check ebay for a rebuilt set, it may be cheaper than doing yours if they are high mileage, any way, good luck-I once saw a mechanic that worked for a used car lot, that specialized in high mileage low cost vehicles, he used a set of fel-pro seats, the brass ones, and actually hammered them into the area around the valve stem-he claimed they would last for 25 or 30 K miles, but it did not look too good to me-have fun.

well after you take care of the problem in the heads...
have you checked the timing?