I agree here. I think with a 10.7:1 compression, you will have your work cut out for you to run this on pump gas...especially with the ethanol swill we have available today. Even with the aluminum heads, I think you are going to have a temperamental engine if you don't spike it with some race fuel. It's also possible maybe your compression ratio is a tad higher than you calculated.

The rule of thumb I hear is 9.5:1 max for iron heads and add a point for aluminum heads so you are a little past the border. I am sure somebody here will chime in that they run more than that on pump gas but every engine build is different. I agree with your logic on the cam choice but maybe not enough cam to bleed it all off?

If this were my motor, I would start with a head gasket change. I used the thick FelPro's on my build (.055" compressed) which helped bring my calculated compression down almost .2 points from the thin gaskets. With thinner gaskets (.039"), I would have been closer to a 10.6:1 which kind of made me worry about being in the same boat as you.

If the AF ratio isn't way lean @ WOT, then you really have two more things to try and fix here. Verify the engine is NOT running hot and/or lower the compression.

I would try to avoid retarding the timing any more than 31* total and that is too retarded in my opinion.

You will get there and your car will burn rubber (reliably) before you know it!