on a 1984 305 ci engine - are the exhaust valve seals same as intake valve seals?

 

Yes, if you want them to be.

 

Yes but exhaust seals are not as important as intake valve seals.

With intake seals, when the valve opens, there's a vacuum under the valve and it can pull oil down the valve stem and into the cylinder.
With exhaust seals, when the valve is open, The pressure of the piston pushing the exhaust gasses out prevents oil from dripping down the valve guide.

Doesn't matter if it's the o-ring type seal at the end of the valve or an umbrella seal on the guide, they are all the same.

 

There is vacuum in the exhaust some of the time, especially with headers (that's how they WORK). Therefore exh seals can leak oil into the exh ports like int ones can.