Ok, I know this is an old thread, but it came up when I did a search.
My engine guy is recomending a full flow filter and I want to use the existing filter to keep the stock look. His advice/reasoning is that the motor we are re-building had the oil ways in the crank completely plugged. His reasoning is that when you shut down the engine, any impurities in the oil will settle where they are, and stay there. With the old Flattie, only part of the oil goes through the filter and so your oil will always have stuff in it. I'm thinking especially with an occasional use vehicle this could be a bigger problem, rather than on a daily driver.

Has anyone had experience using the existing oil canister, and converting it to a full flow with a spin on filter?

Thanks in advance,
Steve