[Cliff R]

What distributor? What has been done to it?

We use a different approach for each type of distributor when it comes to building an advance curve for them.

For the most part I do NOT use, or work on aftermarket "high performance" distributors. If/when I end up having to use one here, it will usually be the MSD ready to run unit, simply because it is very simple, and has a vacuum advance. The MSD billet distributor is a nice part, after you remove and zinc plate all the internals (they rust just looking at them), but we use and highly recommend a vacuum advance on ALL of these engines.

Anyhow, I will repeat this part, it is DIFFICULT, if not near IMPOSSIBLE with some of these aftermarket distributors, and aftermarket part (spring/weight kits) for stock distributors to get a decent advance curve.

The aftermarket stuff will more often than not use parts that increase the leverage of the weights on the center cam so the curve is much quicker, and difficult to control, plus more times than not they put some of the curve in at idle speed.

This fact makes idle tuning very difficult, and at times impossible. I'll bet that 9 out of 10 carburetor "issues" when it comes to idle tuning are actually distributor problems instead. I would also add here that currently there is some PURE JUNK available for these engines coming in from off-shore. They look like factory HEI's, but the parts are "soft", and the quality of them is simply OK to PATHETIC. I don't want any of them sent here for any reason. Until the supply of factory HEI's is completely gone, we'll keep working with stock units and continue to get the results we are looking for with minimal effort.

I'd like to have $1 for every phone call or email I get from folks who tell me that they can NOT get their engine to idle well, and it slows or stalls when the transmission (automatic) is placed in gear. They will have dozens of questions about the carburetor and setting up the idle system, when 90 percent of the time the cure is to remove the POS advance weights/springs that have been installed and put in something that does NOT allow any timing to be added below about 900-1000rpm's.

Once they do this, and the timing now becomes ROCK SOLID at idle speed, the carburetor "issues" go away more times than not........Cliff

PS: I'll add in one more thing here so I can make a few more enemies. We do NOT advocate using manifold vacuum to the advance for most of these set-ups. Despite reading the long/lengthy and heavily regurgitated information on this subject using Google searches, that information is very good, but flawed in several areas.

IF you find that you have to run the timing clear off the scale, or add 15, 20 or even 30 additional degrees of timing to make the engine happy or want to stay running, then you have fundamental issues someplace else, such as too much cam and not enough compression, your carburetor can NOT supply the needed fuel at the engines current vacuum reading at idle, or combinations of several other problems. Basically we NEVER use tons of timing to curve running issues with these engines, you have problems in other areas and more times than not that is simply a "crutch" fix instead of finding and correcting the "root" issue(s).....IMHO

Even with that said, some engine like a little more timing at idle, so we tune all of them on a case by case basis, but most of the ones we build and tune here do not want, like, or need a ton of timing at idle speed to be happy.....FWIW