78 sc timing and idle question
 

Hi all,
After top end rebuild I have 2 questions. Car has 33,000 miles and is stock. After the break in period, I have checked timing and at idle 800 ish rpm, if I put the timing at 5 degrees, the idle at 6000 rpm is like 31 degrees. Is that ok or a problem? If a problem, what are my options?

Second question, after warm up the idle is 800 ish, sometimes while coming to a stop, the idle drops to 500. Sometimes it dies and other times it jumps back up to 800 and all is well. Thoughts?

You likely have some air leaks. You can check by removing the oil cap when running and warm, the engine idle should drop, if not then it's pulling air from somewhere else.

Investigate and correct air leakage.

Get accurate readings at 1000 RPM on a warm engine.

I just checked the oil and the idle does drop when oil cap removed. I guess next steps are to adjust idle and check timing

I'd bump the idle up to 950.

950 Is better.

if you blip the throttle and the RPM drops down then comes back up to 950, you are a tad too rich.