When I bought my 66, the previous owner had replaced the carburetor with a later model 1100 that he said came off of a Cougar. The car runs fine with the carb but the fuel mileage is pretty bad. I removed it today and found that it does not have a spark control valve and the body is not threaded for one so, I am guessing they deleted it later in production? The bowl vent has also been deleted. The main jet size is 69. Looking in the 66 Ford service manual, the 69 jet would be correct for a 3 speed but, this is a newer carburetor. I found an original 66 3 speed 1100 and cleaned and installed a master kit from Mikes in it but cant get it to run right. It idles great but bucks and snorts when I accelerate. I spent a day trying everything I knew to try with it but could never get it to run right so I re-installed the Cougar carb. Now, after thinking about it, Im wondering if my timing was off with the original 66 carb because it does have a spark control valve. I never thought to check the timing when I had it running with that carb. I wonder if it was a timing advance issue causing the bucking. It ran like it was super lean. Could juts be a bad carburetor too. Any ideas?