Hot start problem. Rough idle and Tach jumping.

Hello, I've got a quick question before I leave for work. This morning I took my car for a ride and it runs great as usual. The problem is, when I let it sit for about twenty minutes, after I turn if off, then restart it, it runs rough and the tach jumps.:dontknow: Any ideas, please post your opinions. Its a 318, two barrel engine. It's been given a full tune-up, including a new distributor(stock), fuel pump, voltage regulator. I may go to a four barrel set-up anyway. It's looking very costly with the Viper engine set-up discussed in my other thread. http://www.forabodiesonly.com/mopar/showthread.php?t=104506. I'll have to make a decision on that soon. Anyway...... Any help would be greatly appreciated.