These are a cleanable and re-usable filter and they are often overlooked. They are used on the small block motors and the big blocks alike. My 327F powered 1966 Sea Skiff has them and my 427 motors do too. They are cleanable.
On the Skiff I opened the drain plug on the bottom and the filter was so full of sediment that nothing came out the open bottom of the canister. Upon taking the device off and looking, I found at least a 1/2 inch of junk nicely layered on the bottom of the filter housing. A little carb cleaner did the trick.
However, there is something that is overlooked on these filters and this is the o-ring. This o-ring stands between you and fuel in your bilge so it is prudent to look at the condition.
The photo below was taken last night as I put my cell phone down under the opened canister and took a photo of the o-ring so I could see it. I suppose I could have done this with a mirror but the cell phone was there and it is a VERY useful tool in working on boats. Here is what I found.
The o-ring just did not look right.
Therefore based on what the photo looked like, I pulled it out and this is what I found.
That tubular device in my hand next to the o-ring is the actual filter stem that fits inside the canister.
I am planning on keeping this filter operational on the boat, but I am also going to use two other filters; one is a big RACOR water separator type to get all the crap that is sure to be in an old boat tank, and then after the fuel also goes through this one I will use a final filter bolted directly to the carb just to be sure there are no pieces of junk coming off the fuel filter itself.
Mine are totally trashed, just wondered if anyone had a stock of these things sitting on a shelf somewhere.