Originally Posted by ggevaert
The engine I purchased online (350 sbc) has a mechanical 4 degree advance (in the timing chain) which I verified manually.
So, next step is to do the timing and I need some assistance.
For a stock chevy engine advance is 6 degrees, so, for this engine do I:
1. add the 6 degrees to the mechanical 4 degrees for a total of 10 degrees.
2. put it at 2 degrees with the thought being that it is 4 degrees below zero (retard) so plus 6 is 2 degrees
3. other thoughts are appreciated.
You have two different things going on here. One is the cam
timing (or "phasing"), the other is the ignition
Even though changing the cam timing (or "phasing") also changes the ignition timing (if the distributor were installed when the cam timing was changed), cam timing is a separate issue from the ignition timing.
So in your case, you can ignore the amount of cam timing change you made w/the timing gears when it comes to setting the ignition timing. In other words, nothing needs to be added or subtracted from the ignition timing, regardless of where the cam timing is set.
In most cases, the cam manufacturers design the cam w/some amount of advance already "built in". The cam card specs will show this. This means in most cases, installing the cam straight up (no advance or retard) is the best way to go.
For the ignition timing, you can use more than 6 degrees BTDC in almost every case. The page cdminter59 linked to has info on setting up the distributor w/an advance curve suitable for how the vehicle will be used and the other things that need to be considered.
What cam is in the engine? Do you have the engine specs?