sounds like the timing chain has stretched to the point of jumping the cam
gear and/or the nylon material composing the outer portion of the cam gear
has worn down causing the chain to jump time............
rotate the crank until the notch on the harmonic balancer is lined up with
the timing pointer and observe the distributor rotor position, it should
correspond with the terminal for #1 or #6 in the dist. cap..............if
it don't line up with either of these then replace the chain n gears.
'79 Chevy K-10
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