Your idle timing is too low...Total might be ok, but my guess is you have a pretty big spread between them. I use a Firecore distributor on my Hemi and I shortened the mechanical advance to about 8*....So it idles at 20-22*, and hits 30-32* at 2500 or above....Now your engine is smaller, and handle more total than mine, but it will like more timing at idle. As much as you can without having trouble starting it. Total on a 484 Hemi we were anywhere from 34-38*