Need Help building a 400 for my 68 plymouth valiant

My questions are:
Are the "906" heads worth it?
What kind of piston should I use to get the compression close to 9.1?
Do I use the 440 rods or 400 rods? (Im a little bit budgeted so this is going to take some time to do)
What other parts do I need to swap a big block into my abody?
Would I stock 727 with a shift kit work if I use it mostly for street?
I'm sure there will be more questions coming