Wow, you got me stumped with this one. I would think with the plugs getting black that has to be excessive fuel. Maybe try a hotter plug? I have no idea what the vacuum should measure.

Hope you figure it out...

Pat,
Been a bad month on several accouts......
Discovered only pulling 12 inches on the vacuum......but will a high lift (currently unknown) cam only be 12?
New brake booster that was on the truck is small, but with only 12 on vacuum gauge it may be under standards.
With newly rebuilt carb, still idles the same. Still cant make engine stumble any worse by closing down the air/fuel mixture screws. Still opened 1 1/2 from closed.
Even though I cleaned spark plugs with carb cleaner, flattened paper clip down in inverted cone area around porcelain and a steel brush, they will be sooty black after idling in driveway for a 20 minute idle/temp check.
It's been a very elusive problem.

Take care, Kevin

Pat,
Good to hear back....one never knows if they've been stricken by the latest round or not.
Been some "really trying moments" with this purchase. Finally got the brakes to work a little better, but not like they should seeing it was converted to discs up front...I think they should be better.
Took it to local older gentleman, who everybody here claims is the expert, and I believe 'em.
It's got a quick backfire if you give it just a little gas.
He thinks it's got the wrong harmonic, or wrong flexplate/torque converter because of the way is shakes. I was told it had a "cam" in it, but I have never had an engine with a "cam", so I didn't know!
I have learned that I'm looking for part numbers with the 28oz loads.
I will be posting my problem on this site, as I need guidance.

Be well,
Kevin

Hey Pat,
Really enjoying your videos. I have a recently acquired 64 F100 Flareside, but discovering it was perhaps a junk yard build.
Hunting down tail light and rear running light problems, leaking windshield rubber, and dash gauge problems next.

My dad grew up in New Carlisle, IN. His dad worked at Studebaker for just over 15 years, came in one day and they shut down.
Dad joined the USAF in '56. Always enjoyed visiting up there, where the air is cooler!

Have a safe weekend,
Kevin