You mentioned that you have a mild cam in that engine so you'll need to find the sweet timing spot for that particular cam in conjunction with your other bolt-on goodies. I would say that the 5* is not enough advance in your case. Try reving the engine to 2000 RPM, check the total advance there, then do the same thing at 3000 RPM, and see what you get for total timing, with the vacuum line disconnected and plugged of course. As previously stated, most small blocks like between 34* and 38* total. Once you're set in that ballpark, then just re-check your timing at idle again. I bet it will be more than 5* - probably 14 to 18*. :)