Intermittant Dieseling

[my new 72]

It only happens when the truck has been driven enough to get ggod and hot, and then driven relatively short distances afterward. It also tends to idle higher than it should when it gets warm? The timing is set to 12 btdc. The engine is a fresh built 383 bored .040 over Sportsman II heads w/2.02-1.60 valves. A crane energizer 274 cam w/ .454 lift. Topped with an RPM Airgap intake and Edelbrock 1411(750cfm) carb fed by a regulated Holley blue electric fuel pump. The ignition is an MSD 6al Super Hei unit. Overall compression is 10.2/1. What do you guys think could be the issue. Worn distributor springs and weights maybe? It also has a little hesitation on takeoff, but again this is only an intermittent problem. Thanks for the help guys.

I forgot to tell you that usually it starts right up after it has been started up and driven once, but after it deisels and I try to start it, I have to pump it a little to get it to fire. Thanks again.