Guess The Compression Ratio

What do your plugs look like? It sounds to me more like you are a little lean on full throttle. Your timing is conservative. Which may be a good thing. You really dont want to detonate with those pistons. What is the cylinder cranking compression? My guess is it will be close to 180 psi. Try jetting up 4 sizes on the main jets, or down 2 rod sizes on an Edelbrock with the same jet.