I've been going over the final prep on the jeep for the rubicon. (plenty ahead of time!) After installing a new carb adapter (seen in build thread) over the weekend, changing oil, checking spark plugs ect...... went ahead and threw the timing light on for a checkup. I found the timing to be right at 5 degrees @ 650 rpm, vac adv disconnected. Revved up to 3K rpm I only get up to about 15 degrees advance. So 10 degrees of mechanical advance is all I'm getting. I hooked the vac adv back up to the carb and noticed that there was no change in timing advance at idle. I hooked it up to manifold vac and still no change in advance. I pulled the distributor cap and verified that the distributor weights are functional and that the vac advance plate/arm moves with a screw driver. I ordered a new vac advance can. When I checked the spark plugs I did notice that they looked a little rich. Not bad, but rich none the less. My jeep doesn't get very good mileage. Pretty much 10 mpg even when I had the overdrive. It doesn't seem to me like it is hurting for power and runs good but I want to make it even better. The lack of increase in advance at idle when the distributor is hooked to manifold or carb vacuum, combined with the rich condition/ poor mileage; seems to point toward the vac advance can. This is a delco distributor with petronix points eliminator. I have been running it for several years. My question is, how much mechanical advance should I expect to have?