Engine problems 79 chevy 350


Asked by Dec 23, 2015 at 12:16 AM about the 1979 Chevrolet C/K 10

Question type: Maintenance & Repair

Hi I've got a 1979 chevy with a 350 that I bought
about 3 months ago and I'm in dire need of help.
Here's the story. It ran fine with plenty of power
when I bought it but I decided to make sure
everything was tuned up anyways. I timed it and
adjusted the valves and of course knocked a plug
wire off the distributor and drive 40 miles
wondering why it was backfiring so bad. Anyways I
figured it out and put it back on. I kept driving it
and it started backfiring again for no apparent
reason and the exhaust sounded like crap. So I
adjusted the timing again the first time I just did it
by ear and this time with a timing light and
changed the plugs. I also noticed a slap in one of
the rocker arms but just decided to leave it.
Eventually I got it running good not sure which one
of those things did it but about 40 miles later same
thing happened. Put new plug wires in it that were
7mm and it has a high output ignition and points
distributor and ran like crap and finally got new
8mm wires in it. It ran better but still not good. At
all. Put new plugs in it and fired it up and was still
running like crap but I fired it up the next morning
and it was running fine but still a lack of power
which it's had since as long as I can remember
except for when I first bought it. Same thing
happened that day and finally started to notice the
pattern lol. I did everything same as I had before
when it started running like crap except this time
tried adjusting the rocker arm and made it even
worse. I rebuilt the carb new plugs/cap and
rotor/and points in the distributor. It doesn't
backfire but runs really rough making a whomping
noise out the exhaust with a loss off power and no
sign of getting better it's been sitting for a month
and would really like to get it running good again
with good power for more than 40 miles lol. I can't
figure out why this is happening and any comment
would be appreciated thanks.

3 Answers


Make sure you didn't adjust any of the rockers too tight. I've also ran into a couple cases where when I shot ingition timing the car ran worse, what happened is the crank mark didn't correlate tdc correctly. One I just set by ear and road testing. The other I set it to tdc and made a mark on the balancer where it should be then set timing. The only other thing I could think of is make sure the distributor shaft doesn't have any play. No side to side, you will be able to move it up and down very slightly. Also double check fring order, 18436572


Thanks Andrew. I've checked firing order and when I put the new points in and tuned them in the distributor I felt that there was little slack in the shaft like 1/16th up and down was all. I might have to play around with the timing and rocker arms but Idk if those could have this much of a negative effect on it.

1 people found this helpful.

Flat cam, typical of chevy and gm, they use smaller lifters then FORD or MOPAR what happens is they don't always turn and this wipes out the lobes and the lifer face.

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