I'm in the process of putting another carb on my 396, the parts tech made me aware that the 396 was never designed to run with an HEI ignition. He advised to take out 10 degrees. He stated that the engine should see no more than 28 deg advance. He said a normal HEI will advance to 38 deg. At 4000 rpm with the normal HEI advance the motor will lay down. Any thoughts???

I've replaced point’s type distributors with non computer HEI's in many BB & SB and never had any trouble because it was an HEI. My 1970 402 (basically a 396) with a GM HEI runs excellent with 36 to 38 total advance (no vacuum advance).

I'm sure someone will have a good explanation for you.

Although I can appreciate a parts tech advice, in this case he is off base.

It is actually stupid to suggest that the proper total advance is decided by the type of distributor. It is not.

I run 38 degrees total advance on my 496.

Thomas

Plug/play and don't look back.

Hook-up is simple. My guess is HEI's are used by a very large number of TC members.

Try using search for more information.

Thanks for all your responses, I'll just leave it alone. Sometimes you wonder where the Parts Tech came up with that

g,
The main thing to be learned here is that the engine combination determines how much advance you need at different rpm's and loads. Some HEI's do have a lot of advance built in. Others dont have near enough. Vacuum advances have different rates and amounts of advance too. Everything has to work together for the engine to run its best under all conditions.
If you really want to learn about this subject, a VERY good book is:

The Doctor's Step by Step Guide to Optimizing Your Ignition by Christopher A. Jacobs

I have it and learn something new every time I read it. Its available on Amazon.com.

Bill: Thanks for the information!!!

g,
The Doctor's Step by Step Guide to Optimizing Your Ignition by Christopher A. Jacobs

I have it and learn something new every time I read it. Its available on Amazon.com.
Awesome book, and a pretty good ignition system.