Ok following up on this thread, I FINALLY found the issue and it wasn't with the BW-35 (although getting the kickdown cable set correctly did help overall). The car is running a pair of HIF6 carbs with a stock Volvo airbox. The holes in the airbox line up with several holes on the carbs and someone in the past actually ending up tapping a hole that matches the airbox holes but is in fact a air input for the "accel pump" mechanism on the side (The device on the side with the "dripper" output). That means my HIF6 carb had 5 tapped holes instead of the correct 4 tapped holes. When I reinstalled the airbox I chased all the threads on the carb with a tap and this sent aluminum shavings into the body of the carb, including the float area and "accel pump" mechanism on the side. Why the carbs ran fine for several thousand miles with these shavings in there is anyone's guess, but definitely cleaning out these shavings from the carb float area solved the issue I was seeing. I guess that goes to show that sometimes the problems ISN'T the last thing you changed! (BW-35 in my case)

Brian