GMC Repair: 1977 GMC 250 inline 6-cylinder wrong wires to plugs, exhaust stroke, head gasket

Question
i put a new head gasket on my engine and forgot to mark the plug wires. the repair manuals all have the same order but its wrong for mine. i try and start it after changing them the way i think it should be but it either backfires, o out the carb,... i've adjusted the vales correct etc. ... help...ty

Answer
all my 250 gmc's are 1-5-3-6-2-4.

are you SURE your wiring the distributor cap correctly ?

are you SURE you have the distributor set on the #! cylinder on the INTAKE stroke (compression) side and NOT on the EXHAUST stroke ?


The distributor wires go clockwise around the distributor and # 3 is at the vacuum advance unit and going clockwise it goes 6-2-4-1-5.

VALVE SPECS:

intake and exhaust are preset to .0010 - .0027

Then turn each rocker arm stud until ticking stops then tighten ecah stud and additional 3/4 turn.

I checked 4 books with all the specs and pictures of distributor and timing pictures and all are the same.


How are you putting the plug wires and how tight are the valves set ?.


Are you POSITIVE you have the distributror set correctly ?.




autohelp


Let me know.