can you please help,have a stocked 396 put a new eddelbrock intake an a 670 holley avenger, also converted the dist fron points to a msd hei hooked up to the fuse box for a full 12 volts .the engine runs great at idle when you put it in gear it almost dies then comes back. checked for vacum leaks an all seems well,timing was advance to 16 btc thats where it seemed to like it the best ,checked the float level on the carb an it was to high lowerd it an still same can you please help, also checked the plugs an they look great white with a little brown on the edges
phil

Is it an automatic?
And if so, what stall speed are you running?

automatic 400 turbo its stocked

You might have to upgrade to a higher stall speed converter. I had the same problem with my 396. It has a comp cams 292H cam in it, and my stock converter wasn't cutting it. I went out and got a 2800 stall, and it helped a lot. If you are running a stock cam, it's could be you stock converter needs to be replaced. It's just an idea.

Sounds like you're using manifold vacuum to the dist. If you run "ported" vacuum source to the dist., you won't have this problem.

bradly , its a new 670 street avenger the vacum is coming from the carb , the brakes and the trans vacum is coming from the intake manifold. ported vacum is from the dist.?
phil