Gasoline motor sounds like diesel?

[PStansb]

OK - I'm not sure the best way to describe this, but my 305 V8 gasoline motor often times sounds like a diesel engine when I accelerate.

Any ideas what would cause this, or even what it may be?  Again, I'm sorry for the not-so-technical description, but that's what it sounds like.

This is an 81' C-10 with 305 V8, 4BBL.

Thanks,
Paul Stansberry

[ChevyGuy]

Exhaust leaks?

[toplessblazer]

Spark knock. You may need to time your engine and try running higher octane gas

[PStansb]

I've owned an 80' before that did the same thing and it WAS as simple as running higher octane.  However, I am already running 91 octane in this one and it hasn't resolved the problem.

I'm about to replace the spark plugs and wires...  do you think that would help?

ChevyGuy - When you say exhaust leaks...  what do you mean?  How would that cause the motor to run this way?

[Lt.Del]

Retard your timing a tad.  That is the sound of your valves clattering when you accelerate.

SgtDel

[ChevyGuy]

The knock is also part of it running bad? I had exhaust leaks before that made it sound that way thats why I said that.

[1976Scottsdale]

This one is a definate long shot, but mine did it twice before I got the message that it was broken.  Make sure that your distributor itself in all the way in.  Mine was hanging out about 3/4 of an inch.  It ran, it just hammered really hard.