If you use WIX filters and your engine is the same as a Branson 35 then the numbers are as follows: lube= 51344, Hydraulic= 51202, Air= 46438, Fuel= 33263. Those are the Wix numbers that I use for my Branson 4020 which is the same engine as a Branson 3520 (except for turbo). May I also suggest going to http://www.filter1.com/ and set yourself up with an account, its very simple and the prices are very reasonable. Hope this helps.