Hey guys, do these symptoms sound like a bad convertor? I just finished installing a brand new .040 overbored 350 ci into a '86 GMC shortbed pickup. This is hooked to a 1979 th350 stock long tailshaft transmission. Engine fires up, idles, and runs great. The problem is when the truck is idling in gear while stopped, as if at a red light. The engine almost stalls, shaking and rattling until accellerating to about 1500 to 2000 rpm then everything smooths out until the next light. Cruising down the road with no load on the engine I can feel it be not smooth, if that makes sense. Idle is set at 680 in gear. Cam lift is .495/.510. Timing at idle is 12*. Thanks for any imput