440 power gains/ aluminum head advantages?

5 degrees retarded can be a big deal. What is the static compression ratio? If it's under 9.5, it probably wouldn't hurt a thing to get it down around 102 intake center line. I wouldn't even be afraid of 100.
with the calculator on summit i'm right at 9.5 with everything. i installed it at 105.5icl. i hope im not missing out on anything by not having it a little lower. initially at 0 on the crank sprocket i was at 102.5. but i brought it up to get it as close to the 105 as possible. but at some point i want to go to aluminum heads and swap the cam to a bigger lift roller. i got it all back together though and cold starts and throttle response seem to be much better. and it seems my timing jumping around was in the timing chain slack because it's gone now with the new 440 source chain. i plan to get it out tomorrow and see how it drives! i also got some new 275s for the back so i dont have to drive around on slicks on the street anymore ha.