396 big block misfiring

I have a 396 big block in a 1968 chevy c10. I have been told it has a cylinder that is misfiring. It is the original engine. Should I have it rebuilt, put in a newer engine or get the cylinders all set? I know absolutely nothing when it comes to engines. I just want to enjoy this truck and not break the bank.

Lots of potential causes, some cheap (ignition: points/plugs/cap/rotor/wires), some not (worn out engine). How long have you owned it? When was the last tune up? Have you had the compression checked?

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First do a compression check. Proceed from there. Assuming you have the origiNal ignition system, plugs, points distributed cap, and ignition wire may be due for replacement.


first check the sparkplug and wire on that cylinder. it could be something as simple as that. if that checks out have a compression check done.

I have owned it for 3 yrs. Tune up 2 yrs ago. Im pretty sure the compression was good. Its been siting in garage, so I dont really remember.

Check the rotor also, new cap condenser rotor points plugs and wires would be what I would do. Also check the color of the spark! All pretty simple and cheap compared to a rebuild. +1 for compression test.

What are the symptoms? Does it have an original engine with a carb? If it’s been sitting the gas could have gone bad, or the carb could need a rebuild.

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maybe a stuck lifter from sitting a long time

symptoms are just really shakes alot when idling. it is the original engine and carb. I have gone through a few tanks in the past couple of years so i dont think its the gas.

How long has the gas been setting in the tank?
We could easily burn a tank in one evening cruising in a 396 El Camino.

probably 6 months. i was driving it last summer with the shaking.

something easy you can try… if you have a really dark area. no lights. park there with the engine running, pop the hood and stare at the engine. let your eyes get used to the dark. look and see if you see any sparks jumping. bring a flashlight. if you see sparks jumping, put the flashlight on to see where its coming from.

Thanks. what does it mean if i do see sparks jumping?

a bad wire

Great. Thanks.

Has it been shaking the whole time you’ve owned it? How many miles on it?

Yes. 104,000. I just thought it was supposed to be that way because its so old.

It means there is firefly’s in your engine bay. Sorry I couldn’t resist my resistance level is low today. :laughing: :laughing: :laughing:

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I wish that were true.

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Seriously though you can tell a lot about the wiring that way be it a wire that is rubbing and shorting out or a posable break or loose connection in the old days I have found and fixed a lot of problems that way.

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