Engine turns over but will not crank. Checked related parts on 2001 Chevrolet Express 1500

Fuel pump works, fuel filter new, checked fuel test port (getting fuel), new spark plugs spark, iginition coil works. Replaced dist cap and rotor. Equipped with SFI system but testing is limited. Cannot verify fuel presence in ports. No known fuel system fault at this time.

Check for ignition fire at the plugs and fuel pressure at the test port with a gauge!!
Thanks. First fuel presure test seemed ok. Used different guage and verified pressure was only 50psi, needs 60-65psi. Replaced pump.
Common problem with GM.