Steering valves with port blocks can be identified by the presences of a thick plate sandwiched between the steering unit valve body port face and the the hydraulic lines coming to your valve. Port blocks can be used to add protection circuits to ease high pressure surges occurring in the steering system or simply used to change the hydraulic line/hose routing. We may ask you if your steering control unit has a bolt-on port block as occasionally our stock replacement valves are not compatible with port blocks, but if known we can often find or create a replacement for you that will work with these. There should be no paint between the steering valve and valve block and also no spot facing around the port openings which would reduce the height of the port face. Contact us with any questions and please see these attached pdf’s for reference.