Hi Minger. Good fatigue data on aluminum is hard to come by, especially charts showing test results.
MatWeb has some data depending on whether it's a sand cast
part or permenant mold
cast. Note the ASTM specs for these are B26 (sand) and B108 (perm mold).
I've designed a number of sand cast parts are highly stressed and under cyclic conditions and the only data I've been able to find is the matweb stuff which I've had to depend on. Seems to be ok, though I've always put lots of extra margin in.