Originally posted by urotu

My question lies with the initial stabbing of the distributor, can you do the same thing somehow with an HEI? That is, make the light go off and on by moving the dizzy to determine you best spot to set initial timing? Just interested to know. I am going to copy and paste this into some of my own stuff to use for future reference. Great stuff.

I do very much what DennyW and thesals do with HEI.

I usually know where true TDC (Top Dead Center) - and I'm sure they do as well - is and I set the engine at the initial timing mark and not zero.
For my 462" Buick it's set at 8 degrees BTDC. (Before Top Dead Center).

For timing I like to use a spare spark plug plugged into the #1 plug wire.
The plug has a grounded 14 gage test lead clamped around the hex or threads and the plug either hanging in plain view or lying where it's not going to interfere with V-belt or fan.
In either case, the electrodes are set so I can see the arc.

Since the Buicks rotate CW (Clockwise) I like to turn (retarding timing) the distributor CW about 20 degrees.
This takes the play out of the distributor drive stuff going one way.

With ignition on, turn the distributor CCW (Counter Clock Wise) advancing the ignition until you see an arc at the spare spark plug.
Stop there and bolt the distributor lock bolt down.

This sets up the timing very accurately and when you start turning the distributor CCW you'll take the distributor play out of the picture going in the direction it will be - mechanically loaded - when it's running.

After that, double check with a timing light when the engine is running and you're in business.
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I see a lot of talk about timing an engine with a vacuum gauge or by ear.
Some guys do that and their cars run ok.
I do see them turn the distributor quite a ways in most cases and my opinion is the timing can be off at least 5 degrees one way or the other.
Dyno - and the dragstrip - testing show gains or losses in performance when the timing is just a couple of degrees off.

Using a timing light or changing timing statically as described above is the only way you're gonna know exactly where you're at as far as initial timing goes.

Close enough is not good enough and to my way of thinking if you don't use a timing light you're depriving yourself of a lot of important information.