looks like what was/is being used on some 1999 and up Workhorse chassis's. They no longer make the 3 port filter but they sell you an adapter and a 2 port filter now. Then you can use a GF652 or GF481 filter that can be found anywhere. This WHG481FK filter can be purchased at any Chevrolet dealership for around $50 or at the web site below. I don't know if it will work in your case. You can search "fuel filter" in the Workhorse section and find a lot of info on this filter.
Thank You for the pictures Oemy.
06 Hurricane 34FT WH W20 Chassis 8.1L 120K, Steersafe, Koni Shocks, DIY Trac Bar, Tri-Metric 2025RV Battery Monitor, 4-6V Batteries, Scan Gauge 2, Crossfires, 735W Solar Morningstar MPPT-60, KVH R5 In-Motion Sat, XM Radio, 07 Chevy Malibu Maxx Toad, Falcon 2, Brake Buddy, Escapee