Why no choke, it hurts nothing to use one and makes for instant starts in any weather and fast idle for warm-up.
When you add vacuum advance you can lean up the APT a bit because it will allow the engine to burn a much leaner mixture w/o drivability issues.
Not uncommon at all to see 15-17 to 1 A/F at very light throttle depending on engine load, throttle position and RPM's. Since the VA is a load sensing device, the additional timing drops right out and you go on the mechanical advance curve with any heavy throttle or heavy engine load.
My engine makes over 550hp/600tq and I use an electric choke on it and VA. It's higher compression (11.3 to 1) so I only add about 14 degrees from the VA at light load (ported vacuum), 10 degrees initial timing and a 20 degree mechanical curve all in around 3000rpm's.
I ran a few years w/o a choke because I was racing the car a lot and not much street driving. About 15 years ago I put the choke back on it because starting it up to move the car around in cool/cold weather was a serious PITA. It will now fire right up in any weather, even tested it well below zero outside and it roars to life instantly. Without the choke I'd have to pump it dozens of times and it would only run 3-5 seconds then stall out. I'd have to repeat that cycle and "feather" the throttle to keep it running till some heat got into the engine.
I thought the choke might slow it up some at the track, but it runs exactly the ET and MPH with or without it.......FWIW.......Cliff
