Street Demon tuning experience

13:1 cruise *seems* rich but based on my experience and what the Street Demon instructions say that's close to ideal (instructions say 13.5:1).

I still think the outer ring on the harmonic balancer slipped which is why your ignition timing advance is reading so high for how it runs. I think next order of business is to verify TDC with a piston stop tool.

Also adjusting the advance by 5 degrees is quite a bit, it can be tricky but changing it in increments of 1-2 will get you closer to ideal and can make a noticeable difference in response, power and fuel efficiency. The more advance you can run without pinging the less hesitation you'll experience when opening the throttle and will be able to run a leaner mixture without stumbling or hesitation. I just finished doing this on my D200 pickup (360 with Edelbrock 1406 carb and Summit Billet distributor); it took quite a while to get it fully dialed in with lots of back-and-forth adjusting timing then carb then timing then carb then timing (lol) but it runs awesome now. It is true you should get the timing dialed in first, only reason I was changing it after carb adjustments is that I don't have a WBO2 sensor on my truck and am tuning it based solely on feel; it ran good but my gas mileage was lower than normal so I leaned out the primaries which caused it to be stumble-y off idle. I then modified the the distributor to allow more initial advance and slightly quicker mechanical advance curve with the same total advance while also adjusting the vacuum advance pot a bit (less advance relative to vacuum) and now it's smooth as silk.

Tuning can be a pain and tests your patience but it's SO satisfying. I barely have to touch the gas pedal now to get the truck to accelerate and maintain speed up hills which there are a lot of where I live. When I step on it the torque is instantaneous, the truck really moves from a standstill in an impressive way considering it weighs 4400 lbs and has a 727 trans with stock 1800-RPM stall converter, 3.54:1 axle gears and 33" tires.