305 idle problem

I just recently swapped a stock mid 80s 305 out of a motor home into my 83 Malibu. The motor ran when it was pulled (saw it running) and then it sat in a heated and closed shop for about 3 months. The motor and tranny are now in and buttoned up and I have used a V8 wiring harness from an 81 Malibu. The issue you I'm having is it will only start and run at full throttle and then it runs like a piece of junk. I pulled the old Qjet off and put on a freshly rebuilt one (done by professional) because I suspected it might be flooding itself but it's still doing the same thing. I know for a fact it isn't timing because it hasn't changed since it was in the RV. And I can't find the source of a vacuum leak to cause a problem like that. When running with either carbs you can smell that it's rich, I will say that when I put on the rebuilt Qjet the exhaust smelt more of a "pure" rich smell rather then nasty rich smell with the old Qjet. I'm kind've at a loss right now, anyone have any suggestions?

I can't remember, but does your Malibu have the Engine Control Module? If so, is it wired in or eliminated?