There are 3 types of 261s. none are like the photo in the article except the 1954 which is best run W/O a filter.
The later 261 60-62 have two large holes which can be 'plumbed' like the pictures unless your using that for a motor mount.
The 55-60 models can be run with or W/O. There is an article here about that.
No matter which one you have the 'by-pass' canister won't work as the fitings are to small for 'full flow' operations.
Good luck, John M.....
