Denny is right I went thru the same thing with my 216 tell I got a W1 on her and she ran great after went to Kansas city and back got 16 MPG and NO trouble with the later 235s You.re going to have to find a YF carter the W1 is to small I just installed a 55/235 in My 52-3100 and found a YF4480s carter rebuilt it and am installing on the engine soon. There is a down side to the YF the pump is made out of a material that gets hard after a year or so with modern gas ,but I don't really care if I have to rebuild the carb every year or so ,as long as it makes my truck run good whats an afternoon working on my truck I'm doing that anyway.
There are alot of different YFs that You can use also Carter-Weber options search around and read up theres ALOT of info out there.
Pete
