Faulty distributor?

[adkphoto]

I seem to have no shortage of issues to bring up this year... so here's another one :-)

I just rebuilt the ol 350 including a built-up set of Vortec heads, new timing gears, mild cam (204/214 duration) etc, but kept the old HEI distributor. I did upgrade the coil to a Hi Po Accel unit however.

I've only been able to fire it up a couple of times because I fried the starter (bummer), but while I was breaking the engine in, I noticed that the idle wasn't as smooth as it should be. Varied about 100 RPM, worse at low engine speeds. Had the same problem before I rebuilt the engine too.

I was real careful setting the lifter preload during assembly, so I doubt that's the problem. I'll definitely double-check it after the engine's broken in a little more though.

My question is, is the erratic idle a symptom of a faulty distributor? Are there any other symptoms?

Also, what type of aftermarket HEI distributors are you all running? I've got my eye on a Mallory unit from Summitt that has an adjustable advance. At $130 without the coil it sounds like a bargain.


David

[Randy70C-10]

Your ignition module may be going bad.

[mrein3]

2 or 3 weeks ago I decided to see why my truck was running bad and clacking away on the passengers side...
Yup the dreaded chevy small block flat cam. If I had a nickle...

Memorial weekend I stuck a new Comp Cams something or another that my engine rebuilder friend recommended.
When I got done with that I had all 8 cylinders again but it ran like crap. I could barely pull my boat 50 mph.
This past Saturday I disconnected the vacuum advance for a trip to the compost. On the way home I bought a stock replacement vacuum advance.
Problem solved.

I kept thinking the timing was off (no tach) because it ran good in the driveway with the timing light attached...
But if you follow the procedure to set the timing you disconnect and plug the vacuum advance line.

To make a VERY long story short check your vacuum advance on your distributor. When the fail they sometimes fail after they advance you a little bit. This puts you in a mode where the timing keeps advancing and retarding which could give you the results you are seeing.