Aluminium heads seem to be able to run with a bit less total, initial and mechanical, vacuum is not considered when talking about total. I also tuned mine on a dyno and got best numbers with only 28 total. I welded the distributor plate to stop the mechanical from returning to zero for an initial of 16-18. Then only the top of the advance curve is used for 28-29 at 3200 rpm. Started with 32, adjusted up and down and 28 was the magic number. That set the initial at 9 which caused it to run like crap at idle as well as over heat, thus the plate weld.
I have no operational choke or fast idle on my carb. When I first start it idles at 350-400 rpm, has about 5 inches of vacuum and the air fuel ratio is 16-16.5/1. as it warms up the idle slowly increases as well as the vacuum and the A/F ratio drops. If I had the initial set to 12 I would have to warm it up with my foot on the gas pedal.
Never had kick back with this engine, used to get a lot with my 69 GTO. That car had a slow crank and there just didn't seem to be enough momentum to push the piston up when it fired. Was set at 12 initial. I have a High Torque starter in the Bird there was a stock one in the GTO.
