engine shutting down problem

[71chevc10]

Hey all,
My problem is I have a 71 chevy c10 with a 350 with a lunati voodo street performance cam

when i shut engine down it runs on a few seconds before shutting down
I only use 93 octane
would appreciate any ideas
thanks

[geezer#99]

Turn the idle down.
Closing the primary throttle cuts off the air.
If it won't idle nicely slower then increase your initial timing a bit and then turn down the idle.

What's your initial timing?

[davepl]

Here it comes:

If your vacuum advance is plugged into manifold vacuum the extra ignition lead can cause run-on until the engine slows enough that it's not producing enough vacuum to advance anymore.

If it's not that you likely just have too much initial timing. Sometimes people crank the timing too far ahead trying to get a big cam to idle well.

A less common cause would be carbon buildup in the cylinders increasing compression. You could check that with a compression tester (it should be around 150psi, if you're seeing >180, consider it).

[71chevc10]

Thanks for your replies
I will check it out in the am
much appreciated!