95 jimmy

where to begin....i have a 95 jimmy that blew a head gasket between cyl#4 & #6, a blown water jacket on #5 and a bad fuel press. reg. tore down(not first time...licenced mech!) , replaced all gaskets heads up...made sure dist was set per timing thread i read on here, and new press reg. starts ok but is missing and slight poppin through intake. there is not enough vac for brakes...new plugs, cap, rotor, head temp sensor, knock sensor(LEFT HEAD).......HELP:runaround:

Popping thru the intake is either the wrong firing order or a bad valve train component, flat cam lobe, bent push rod, broken valve sping, rocker arm fell off!!