The Napa filter that is better is a #3540. That may be the one you are looking for.
my Spin on secondary and final adaptors filter at 6 microns. The Baldwin sopin on that fits my adaptors is probably better than 6 micron. JT out
How about running a 3336 as secondary and 3626 as final on your adaptors? That is what I plan on running. I will carry a spare if it blocks up. I had my calipers out and it should fit fine. Here are the specs.
Part Number: 33626
UPC Number: 765809336261
Principal Application: Caterpillar 3116, 3126, 3126B & 3126E Engines
All Applications
Style: Spin-On Fuel Filter
Service: Fuel
Media: Paper
Height: 7.090
Outer Diameter Top: 3.180
Outer Diameter Bottom: Closed
Thread Size: 7/8-14
Burst Pressure-PSI: 440
Max Flow Rate: 12 GPM
Nominal Micron Rating: 2
Gasket Diameters
Number O.D. I.D. Thk.
Attached 2.520 2.250 0.110
Part Number: 33336
UPC Number: 765809333369
Principal Application: Agco, IHC, Case, Galion, Hercules, Komatsu, Thermo King (Secondary) (6 Micron)
All Applications
Style: Spin-On Fuel Filter
Service: Fuel
Media: Paper
Height: 7.827
Outer Diameter Top: 3.698
Outer Diameter Bottom: Closed
Thread Size: 7/8-14
Burst Pressure-PSI: 270
Max Flow Rate: 12 GPM
Nominal Micron Rating: 6
Gasket Diameters
Number O.D. I.D. Thk.
Attached 2.729 2.415 0.255