I have a 73 Pinto I use for autocross. Currently I am running the Esslinger setup with 38mm Mikuni's carbs. The guy at the motorcycle shop told me these 38mm Mikuni's are good for about 40hp per cylinder. I currently make 140hp at the wheels, so I'm thinking I'm at about 165-170hp at the crank. I am considering going to a motorcycle ITB setup to try to get more power, while staying legal in my class (no turbo's). Has anybody here done this? If so what size throttle bodies did you use, and where did you source them? I have been told I should go with a throttle body slightly larger than my intake valves. I have the big valves, they are approximately 44.5 mm, which means I'm leaning toward 45mm ITB's. In addition to the big valves, I also have Racer Walsh stage 2 cam, 11.1:1 compression, and a Schoenfeld header tappered down to 2.5" exhaust. Any help would be appreciated. Thanks.