I have been having a few issues with my engine for awhile now. I recently put on a rebuilt carb and that seemed to help out a lot although there are still some problems. The idle seems to surge a little when it warms up. The engine also shook for awhile when I first started it.

Compression is good. I checked for vacuum leaks and couldnt find any unless there is one under the intake manifold or in the distributor.

The car was sitting for 20 years. I was having a difficult time adjusting the valves since the rockers did not have a completely smooth surface to the tips. I also had a feeling the hydraulic lifters might have been seized up a bit. Could that cause this problem? Would replacing the lifters, rockers, and cleaning up the intake manifold with new gaskets fix this? Any other suggestions?

 

If you are removing the intake manifold, I'd replace the lifters with new ones to be safe... Also, what type of rocker arms do you have? Rail type? I'd definately swap them if the tips are not smooth. Did you replace the fuel pump? After 20 years, I'm sure the diaphram is crap and probably leaking fuel into your oil. Just a few ideas.