Throttle Body Shop TBS 10320 TBI fuel pressure tap adapter 7/16 thread TBI fuel pressure tap for 7/16-20 thread standard fuel injection gauge Fits 1986-95 GM TBI applications 2.8L 4.3L 5.0L 5.7L 7.4L Permanently installs inline between inlet fuel line and TBI fuel fitting TBI Silverado Sierra Suburban Yukon Camaro Firebird Caprice The gauge test port is not designed to be removed or tightened and breakage may result voiding any warranty