According to Bill Sherwood, this is the case.

See link below:

http://www.billzilla.org/4agstock.htm

To properly determine if you are rich or lean, and where, you need a wideband O2 sensor.
You can either install it in the downtube of the header collector (reccommended) or at the exit of the tailpipe with a special clampon venturi rig. Response is slower there.

Overall, this engine is pretty good for the sludge. How was the sludge in the pan? I think given the slight rust in some of the bores that if you hone you will need to get new rings. I think that the pistons are usable "as-is" with a thorough cleaning. Given that the bearings show a little...

The cam journals look OK. As for the cam lobes, that's a little harder to tell. From the photos I would say they seem to be in pretty good shape. I don't see any surface fretting or undo wear on the nose of the lobes. If you have a decent micrometer of the anvil depth to measure the lobes (nose to b...

Is that compression wet or dry? If dry, then you could have high leakage from either valves, rings, or both. You need to oil the cylinders and repeat and get numbers. This will tell you if you need to pop the head and do a valve job. I would imagine that if so, it will be time to do a thorough clean...

That looks like a classic "firepath" burnout between the cylinders. This is caused generally by a head and/or block deck surface that is not flat, but warped. I would clean all residue off both the head and block deck, and I would place a straightedge on both of them in turn. Try and do it...