My research lead me to the conclusion that the 235 carbs are 210 cfm and the 261 are 250 cfm. I recently installed a fresh 261 but used the carb of my 235 for initial start up as I knew it worked . I've managed to do about 1,500 miles since and will install the 261 car over the winter at which time I might be able to tell how much of a difference there might be . The 261 carb came with a auto choke , but the top was changed to accommodate the manual choke .
