Idle surge

If you dont have adjustable rockers, the lifter preload may may a little off too. No big deal, but the heads expand as they wamr up. So in many cases, an aluminum headed car will run rougher when cold. If it's fine when at operating temp, I wouldnt worry about it. After the vaccum leak checks, you may also want to check your timing curve. Too light a spring can cause the timing to raise a little, raising the idle speed when it does. It may also just be a little out of adjustment carb wise too.