not an a body but need some help

My 78 dodge warlock is driving me nuts. The truck has a 383 in it runs great until you go over 1/2 throttle for 15 or 20 seconds it loses power and wont run more than 1800 rpm and will die when i come to a stop. Truck will fire back up after about 2 minutes of sitting and run ok at lower rpms. This all happens between my work and house which is about 5 miles on the highway. The truck has a new distributor, new msd street fire box, new coil, new fuel pump,new exhaust, switched carb with a known good carb. compression is 120-130 on all cylinders. The truck has done this since i got it and truck had been sitting for several years any help would be awesome thanks guys