97 bravada/blazer, 133,000 just did new head gaskets, heads milled and magnafluxed at engine shop ok.
1st start, fuel pressure regulator leaking out vacumn inlet, replaced. checked for injectors pulsing and shooting fuel with upper intake off. fuel pressure with key on at schrader valve is 60psi with key on, drops to 55psi and holds with 55psi. compression on all 6 is 140psi. plugs clean and gapped. plug wires good. spark at each cylinder. no oil in coolant and no coolant in oil. 10 gallons fresh top tier 87 octane + lucas cleaner. pulled distributor to remove intake. car rolled six inches in shop in park (prop shaft out) AWD will creep in park. had to reset dizzy at TDC, still wouldn't start, gears on dizzy kept jumping. compared to new dizzy, gears at bottom on old dizzy loosey goosey, bought new dizzy and cap and rotor. set in correctly, f***ing pump shaft, closest it would drop in was a few degrees north of the "6" or a few dgrees south. new camshaft sensor with dizzy. new crankshaft sensor when old dizzy threw 1345 code. battery good. reset ign module with dielectric grease. coil primary side infinite resist, secondary ok. turns over, tries to fire and backfires (induction) through intake. won't start with starting fluid. no vacumn leaks, kicker: started and ran perfect for half hour last week on old dizzy, turned off for the night, never started since. i'm thinking stretched timing chain and/or jumped a tooth. just thought i'd ask before i tear the front off to check

thanks

 

Check the wiring on the cap closely, easy mistake to transpose cyls 1 and 3:





Induction could be caused by the distributor not meshed correctly with the camshaft, P1345 is set when this happens. Distributor could be off 180 degrees, or just a few.

When the distributor is fully seated against the intake manifold, the rotor should point within ~12 degrees of the "6":